Linear from an equation worksheets

An equation is linear when x is only multiplied by a number and added to — anything squared, cubed or under a fraction bends. These free printable worksheets ask it of the equation alone.

Kid stuck on one? You don’t just get the sheet.

Linear from an equation
Linear from an equation worksheet — From the equation, free printable with answer key

The answer key prints on a separate page.

What's on this sheet

One thing decides it: what is being done to x. y = 2x + 3 is a line; y = 2x² + 3 is not, because squaring x makes the graph curve. The standard's own example, A = s², is ruled out for the same reason — its points (1, 1), (2, 4), (3, 9) do not lie on a straight line. Reading the operation, not spotting a shape, is the whole skill here.

Why this sheet works

The trap on every sheet is y = 7. It has no x at all, so a child hunting for the mx + b form does not find one and answers nonlinear — but every point sits at the same height, which is a flat line, slope zero, not "no line". It is the most missed question on this standard, so no sheet leaves it out. This is the from-the-equation half of the topic; the table half is a separate page, because a table cannot be answered by recognizing a form.

How this one works

One question from this sheet, worked through a step at a time.

y = 11x³ + 32

y = 11x³ + 32
y = 11x³ + 32
Linear or nonlinear?Nonlinear
  1. Linear means the graph is a straight line, and one thing decides it: what is being DONE to x. Multiplied by a number and added to — that is a line. Anything else is not.
  2. Look at what x is carrying: it is cubed. Squaring is not multiplying by a fixed number — going from x = 1 to 2 to 3 gives 1, 4, 9, and those gaps are 3 then 5.
  3. So equal steps in x do NOT give equal steps in y: x is cubed, so the steps in y grow as x grows. The graph curves, so it is not a line.