SAT Math

Systems and Linear Inequalities flashcards

0/60

60 cards remaining

All 60 cards in this deckShow
Substitute into a target expressionSolving Systems by Substitution
Solve the pair, then answer the requested combination.
When should I use direct substitution?Solving Systems by Substitution
Substitute an isolated variable into another equation.
What method supports substitute into a target expression?Solving Systems by Substitution
If y = kx, then ax + by = (a + bk)x
Isolate before substitutingSolving Systems by Substitution
Choose the easiest variable to isolate.
Direct substitutionSolving Systems by Substitution
Replace the variable with what it equals.
What must I check in solving systems by substitution?Solving Systems by Substitution
A solution is an ordered pair satisfying both original equations
What method supports isolate before substituting?Solving Systems by Substitution
x + y = s ⇒ y = s − x
What method supports direct substitution?Solving Systems by Substitution
y = mx + b and ax + y = c ⇒ (a + m)x + b = c
When should I use substitute into a target expression?Solving Systems by Substitution
Find a combination of the solution coordinates.
When should I use isolate before substituting?Solving Systems by Substitution
Rewrite one equation to make substitution efficient.
Eliminate to find a combinationSolving Systems by Elimination
Look for the target hidden in a sum of equations.
When should I use immediate elimination?Solving Systems by Elimination
Add equations whose variable coefficients are opposites.
What method supports eliminate to find a combination?Solving Systems by Elimination
If kx + ky = c, then x + y = c/k, k ≠ 0
Scale and eliminateSolving Systems by Elimination
Make matching coefficients before canceling.
Immediate eliminationSolving Systems by Elimination
Add the equations so one variable disappears.
What must I check in solving systems by elimination?Solving Systems by Elimination
Scale every term of an equation before adding; retain signs when subtracting
What method supports scale and eliminate?Solving Systems by Elimination
Multiply an entire equation by a nonzero constant
What method supports immediate elimination?Solving Systems by Elimination
(ax + by) + (cx − by) = (a + c)x
When should I use eliminate to find a combination?Solving Systems by Elimination
Use equation sums to obtain a requested expression directly.
When should I use scale and eliminate?Solving Systems by Elimination
Multiply an equation to create canceling coefficients.
Parameter for a coincident lineGraphical Solutions and Number of Solutions
Every term must scale by the same factor.
When should I use unique intersection?Graphical Solutions and Number of Solutions
Identify when two linear graphs meet once.
What method supports parameter for a coincident line?Graphical Solutions and Number of Solutions
Ax + By = C and kAx + kBy = kC describe the same line, k ≠ 0
Parallel versus identical graphsGraphical Solutions and Number of Solutions
Same direction plus a different starting value means no crossing.
Unique intersectionGraphical Solutions and Number of Solutions
Different slopes lead to one crossing.
What must I check in graphical solutions and number of solutions?Graphical Solutions and Number of Solutions
An intersection must lie on both lines; matching slopes alone do not distinguish parallel from identical lines
What method supports parallel versus identical graphs?Graphical Solutions and Number of Solutions
same m, different b ⇒ no solution; same m and b ⇒ infinitely many
What method supports unique intersection?Graphical Solutions and Number of Solutions
m₁ ≠ m₂ ⇒ exactly one intersection
When should I use parameter for a coincident line?Graphical Solutions and Number of Solutions
Match all coefficients to obtain infinitely many system solutions.
When should I use parallel versus identical graphs?Graphical Solutions and Number of Solutions
Classify systems by comparing normalized equations.
Two rates observed twiceSystems of Equations Word Problems
Different combinations reveal the individual rates.
When should I use count and value systems?Systems of Equations Word Problems
Model a total count and a total value.
What method supports two rates observed twice?Systems of Equations Word Problems
ax + by = c and dx + ey = f
Mixture systemsSystems of Equations Word Problems
Track total mixture and total ingredient separately.
Count and value systemsSystems of Equations Word Problems
Use one equation for how many and another for how much.
What must I check in systems of equations word problems?Systems of Equations Word Problems
Unknown counts should be nonnegative integers and must satisfy both contextual totals
What method supports mixture systems?Systems of Equations Word Problems
x + y = T; p₁x + p₂y = pT
What method supports count and value systems?Systems of Equations Word Problems
x + y = N; ax + by = V
When should I use two rates observed twice?Systems of Equations Word Problems
Recover rates from two different resource combinations.
When should I use mixture systems?Systems of Equations Word Problems
Use weighted contributions to model a blend.
Integer constraintsLinear Inequalities in One Variable
Solve first, then enforce whole-item feasibility.
When should I use positive coefficient inequalities?Linear Inequalities in One Variable
Solve and interpret a one-variable inequality.
What method supports integer constraints?Linear Inequalities in One Variable
x ≤ B/p with integer x ⇒ maximum x = floor(B/p)
Negative coefficient inequalitiesLinear Inequalities in One Variable
Dividing by a negative flips the arrow.
Positive coefficient inequalitiesLinear Inequalities in One Variable
Balance both sides and keep the arrow when dividing by a positive number.
What must I check in linear inequalities in one variable?Linear Inequalities in One Variable
Reverse an inequality when multiplying or dividing by a negative number
What method supports negative coefficient inequalities?Linear Inequalities in One Variable
−ax < b ⇒ x > −b/a for a > 0
What method supports positive coefficient inequalities?Linear Inequalities in One Variable
ax + b ≤ c ⇒ x ≤ (c − b)/a for a > 0
When should I use integer constraints?Linear Inequalities in One Variable
Use an inequality to find a feasible integer maximum.
When should I use negative coefficient inequalities?Linear Inequalities in One Variable
Reverse direction after division by a negative.
Maximum feasible integer valueLinear Inequalities in Two Variables and Systems of Inequalities
Apply all the limits, then choose the largest allowed integer.
When should I use test an ordered pair?Linear Inequalities in Two Variables and Systems of Inequalities
Determine whether a point satisfies a linear inequality.
What method supports maximum feasible integer value?Linear Inequalities in Two Variables and Systems of Inequalities
ax + by ≤ C ⇒ y ≤ (C − ax)/b when b > 0
Intersect two half-planesLinear Inequalities in Two Variables and Systems of Inequalities
A system uses AND: every inequality must be true.
Test an ordered pairLinear Inequalities in Two Variables and Systems of Inequalities
Plug in the point and test the statement.
What must I check in linear inequalities in two variables and systems of inequalities?Linear Inequalities in Two Variables and Systems of Inequalities
A boundary line is included for ≤ or ≥ and excluded for < or >; a system requires all conditions
What method supports intersect two half-planes?Linear Inequalities in Two Variables and Systems of Inequalities
solution region = intersection of individual solution sets
What method supports test an ordered pair?Linear Inequalities in Two Variables and Systems of Inequalities
(a,b) satisfies y > mx + c iff b > ma + c
When should I use maximum feasible integer value?Linear Inequalities in Two Variables and Systems of Inequalities
Combine linear inequalities and discrete restrictions.
When should I use intersect two half-planes?Linear Inequalities in Two Variables and Systems of Inequalities
Require a point to satisfy every inequality in a system.