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SAT Math skill page

SAT Linear Functions Practice

Master slope, intercepts, and function notation so linear relationships feel predictable on SAT Math.

Practice linear functions in DolphinPractice questions
10-16 min practice time3 questions on pageHeart of Algebra
Practice time10-16 min
Question bank3 questions
Best forHeart of Algebra

What this tests

What to know for this SAT skill

Dolphin question bank

Practice your skill

Question 1 of 3Easy
If f(x) = 2x + 5, what is f(4)?
  1. 9
  2. 11
  3. 13
  4. 18
Show answer and solution
Correct answerC. 13

Solution walkthrough

  1. Substitute x = 4 into the function: f(4) = 2(4) + 5 = 8 + 5 = 13.
Question 2 of 3Medium
What is the slope of the line with equation y = 3x - 2?
  1. -2
  2. 1
  3. 2
  4. 3
Show answer and solution
Correct answerD. 3

Solution walkthrough

  1. In slope-intercept form y = mx + b, the coefficient of x is the slope.
  2. Here, m = 3.
Question 3 of 3Hard
A line passes through (2, 5) and (6, 17). If the same line contains the point (10, y), what is y?
  1. 23
  2. 25
  3. 29
  4. 32
Show answer and solution
Correct answerC. 29

Solution walkthrough

  1. The slope is (17 - 5) / (6 - 2) = 12 / 4 = 3.
  2. From x = 6 to x = 10, x increases by 4, so y increases by 12.
  3. Therefore y = 17 + 12 = 29.

Avoid these traps

Common mistakes on this skill

Mixing up slope and intercept

In y = mx + b, m is the rate of change and b is the starting value when x = 0.

Treating f(4) as multiplication

Function notation f(4) means the output when the input is 4, not f times 4.

Reading graph units too quickly

Check the scale on both axes before calculating slope from a graph.

Study plan

How to practice this skill in Dolphin

  1. Practice identifying slope and intercept from y = mx + b.
  2. Move between equations, tables, and points for the same line.
  3. Translate rates and starting values from word problems into linear equations.
  4. Review missed questions by naming which representation caused the mistake.
Practice linear functions in Dolphin

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Skill cluster

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FAQ

Questions about SAT Linear Functions Practice

What is the most important linear function idea for SAT Math?

Slope is the core idea. It represents rate of change and appears in equations, graphs, tables, and word problems.

Are linear functions different from linear equations?

They overlap. Linear functions emphasize inputs and outputs, while linear equations often focus on solving for an unknown.

How should I practice linear functions?

Practice switching formats: equation to graph, table to slope, and word problem to function rule.