SAT Math

Linear Equations in One Variable flashcards

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Why check the original equation?Solving Multistep Linear Equations
It detects sign, arithmetic, or transcription errors; a valid solution makes both original sides equal.
Distribute −3 across 2x − 5.Solving Multistep Linear Equations
−6x + 15. Multiply −3 by each term, including −5.
When is algebra especially efficient?Solving Multistep Linear Equations
When a short linear equation can be simplified and solved exactly with a few operations.
What is a solution of an equation?Solving Multistep Linear Equations
A value that makes the original left and right sides equal.
What must you do when dividing a whole equation?Solving Multistep Linear Equations
Divide every term on both sides by the same nonzero number.
Desmos intersection: which coordinate solves L(x) = R(x)?Solving Multistep Linear Equations
The x-coordinate. The y-coordinate is their common output.
Can 3x and 5 be combined into 8x?Solving Multistep Linear Equations
No. A variable term and a constant are unlike terms.
How do you solve ax + b = c when a ≠ 0?Solving Multistep Linear Equations
Subtract b from both sides, then divide both sides by a: x = (c − b)/a.
If the question asks for 3x + 2, when are you finished?Solving Multistep Linear Equations
After substituting the solved x into 3x + 2 and evaluating it.
Why does adding the same number to both sides work?Solving Multistep Linear Equations
Equal quantities remain equal after the same addition; the equation keeps the same solutions.
Decimal coefficientsEquations with Fractions and Decimals
Shift every term the same number of decimal places.
When should I use clear one denominator?Equations with Fractions and Decimals
Solve a linear equation containing a fraction.
What method supports decimal coefficients?Equations with Fractions and Decimals
0.1ax + 0.1b = 0.1c ⇔ ax + b = c
Clear multiple fractionsEquations with Fractions and Decimals
One common multiplier can remove all numerical denominators.
Clear one denominatorEquations with Fractions and Decimals
Multiply the whole equation by the denominator.
What must I check in equations with fractions and decimals?Equations with Fractions and Decimals
Every denominator is nonzero; clearing fractions multiplies every term, not just fractions
What method supports clear multiple fractions?Equations with Fractions and Decimals
x/a + b/c = d ⇒ cx + ab = acd
What method supports clear one denominator?Equations with Fractions and Decimals
(x + a)/b = c ⇒ x + a = bc
When should I use decimal coefficients?Equations with Fractions and Decimals
Convert decimal coefficients to integers before solving.
When should I use clear multiple fractions?Equations with Fractions and Decimals
Use a least common denominator on both sides.
Negative distributionVariables on Both Sides and Distributive Equations
A minus outside parentheses changes each sign inside.
When should I use collect variables?Variables on Both Sides and Distributive Equations
Solve a linear equation with variables on both sides.
What method supports negative distribution?Variables on Both Sides and Distributive Equations
−a(bx − c) = −abx + ac
Distribute then collectVariables on Both Sides and Distributive Equations
Open the group, then collect matching pieces.
Collect variablesVariables on Both Sides and Distributive Equations
Bring variable terms together with one operation on both sides.
What must I check in variables on both sides and distributive equations?Variables on Both Sides and Distributive Equations
Combine only like terms; distribute negative factors to every term
What method supports distribute then collect?Variables on Both Sides and Distributive Equations
a(x + b) = ax + ab
What method supports collect variables?Variables on Both Sides and Distributive Equations
ax + b = cx + d ⇒ (a − c)x = d − b
When should I use negative distribution?Variables on Both Sides and Distributive Equations
Handle a subtracted expression on both sides of an equation.
When should I use distribute then collect?Variables on Both Sides and Distributive Equations
Solve an equation containing a grouped expression and variables on both sides.
Parameter conditionsOne Solution, No Solution, and Infinitely Many Solutions
For every x to work, match both the x-part and the number-part.
When should I use unique solutions?One Solution, No Solution, and Infinitely Many Solutions
Recognize a nonzero remaining coefficient.
What method supports parameter conditions?One Solution, No Solution, and Infinitely Many Solutions
a(x + b) = ax + k for all x ⇔ k = ab
Contradictions and identitiesOne Solution, No Solution, and Infinitely Many Solutions
When x cancels, ask whether the leftover statement is true.
Unique solutionsOne Solution, No Solution, and Infinitely Many Solutions
A nonzero multiple of x equals a number, so x has one value.
What must I check in one solution, no solution, and infinitely many solutions?One Solution, No Solution, and Infinitely Many Solutions
Classify after simplification; never divide by a coefficient that becomes zero
What method supports contradictions and identities?One Solution, No Solution, and Infinitely Many Solutions
0x = k: no solutions if k ≠ 0; all real x if k = 0
What method supports unique solutions?One Solution, No Solution, and Infinitely Many Solutions
a ≠ c ⇒ one solution
When should I use parameter conditions?One Solution, No Solution, and Infinitely Many Solutions
Choose a constant that makes an equation an identity.
When should I use contradictions and identities?One Solution, No Solution, and Infinitely Many Solutions
Distinguish no solutions from infinitely many.
Unknown in several termsRearranging Formulas and Literal Equations
Gather every copy of the target letter, then factor it out.
When should I use isolate a numerator variable?Rearranging Formulas and Literal Equations
Rearrange a formula by inverse operations.
What method supports unknown in several terms?Rearranging Formulas and Literal Equations
px + qx = r ⇒ x = r/(p + q), p + q ≠ 0
Formulas with productsRearranging Formulas and Literal Equations
Divide by all of the factors attached to the target.
Isolate a numerator variableRearranging Formulas and Literal Equations
Choose one letter as the target and undo its surrounding operations.
What must I check in rearranging formulas and literal equations?Rearranging Formulas and Literal Equations
Record nonzero denominators and coefficients before division
What method supports formulas with products?Rearranging Formulas and Literal Equations
A = bh/2 ⇒ h = 2A/b, b ≠ 0
What method supports isolate a numerator variable?Rearranging Formulas and Literal Equations
y = mx + b ⇒ x = (y − b)/m, m ≠ 0
When should I use unknown in several terms?Rearranging Formulas and Literal Equations
Factor the requested variable before dividing.
When should I use formulas with products?Rearranging Formulas and Literal Equations
Solve a product formula for a selected factor.
Related quantities and a constraintLinear Equation Word Problems
Use the relationship to avoid introducing an unnecessary second unknown.
When should I use starting amount and constant change?Linear Equation Word Problems
Model a fixed starting amount and repeated equal additions.
What method supports related quantities and a constraint?Linear Equation Word Problems
If B = A + d and A + B = T, then 2A + d = T
Compare two plansLinear Equation Word Problems
Write both totals using one variable, then make them equal.
Starting amount and constant changeLinear Equation Word Problems
Separate what you start with from what changes each time.
What must I check in linear equation word problems?Linear Equation Word Problems
Define the unknown and check nonnegative or integer constraints when the context requires them
What method supports compare two plans?Linear Equation Word Problems
a + bx = c + dx
What method supports starting amount and constant change?Linear Equation Word Problems
final = initial + rate × intervals
When should I use related quantities and a constraint?Linear Equation Word Problems
Express related unknown quantities with one variable.
When should I use compare two plans?Linear Equation Word Problems
Set equal two expressions that describe the same total.