Grade 8 · Year 9 · Class 8 · ages 13–14 · Algebra

Linear functions, finding y: Grade 8 practice

Using y = mx + b to find y for a given x. Eight questions at a time, instant feedback and a mastery score from 0 to 100.

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The idea in one minute

Substitute the value of x, multiply by the slope m first, then add the intercept b.

Try these on paper first

One question at each level. Tap a question to see the answer.

Easy If y = x + 8, find y when x = 2:
Answer: 10
Medium If y = 3x + 4, find y when x = 0:
Answer: 4
Challenge If y = 5x + 9, find y when x = 1:
Answer: 14

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Printable linear functions, finding y worksheet with an answer key (new questions every time)
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Related skills

Slope between two points (Grade 8)
Laws of exponents (Grade 8)
Equations with x on both sides (Grade 8)
Simultaneous equations from a sum and a difference (Grade 8)

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FAQ

Linear functions, finding y: questions

What grade is linear functions, finding y?

It is usually taught in Grade 8 (Year 9 in England, Class 8 in India, ages 13–14), though schools and countries differ. Try the grade above or below if it feels too hard or too easy.

What does a linear functions, finding y question look like?

For example: "If y = 3x + 4, find y when x = 0:" The answer is 4. Substitute the value of x, multiply by the slope m first, then add the intercept b.

What should I learn before and after linear functions, finding y?

Before it, try laws of exponents (Grade 8). After it, move on to equations with x on both sides (Grade 8).

How can I get better at linear functions, finding y?

Substitute the value of x, multiply by the slope m first, then add the intercept b. Practise a little every day, read the hint after each wrong answer, and use the printable worksheet when you want to write it out.

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