Which of the following equations is linear?

a. y = x²

b. y = 3/x

c. y = 3x + 2

d. xy = 4

Answer= C

A is a parabola, so it'll look like a "U" shape on a graph, not a line. A is incorrect

B would look like two curved lines on a graph, so it's not linear.

C is in slope-intercept form, which is a big clue that it's probably linear, which it is. C is correct.

D would look like two curved lines, so D is incorrect.

There are three main forms of linear equations.

      Slope-intercept                    Point-slope                               Standard

          y=mx+b                               y−y₁=m(x−x₁)                              Ax+By=C 

Slope-intercept  = m is slope and b is the y intercept. 

Point-slope =  m is slope and (x₁y₁) are point on the line. 

Standard = a,b and c are the constants 

Equation c is linear => y = 3x + 2