find the slope and the y intercept of the lines: 2x-y=9

Question

find slope and y intercept

Answer 1

Hi Billy;

2x-y=9

Slope-intercept form is y=mx+b.

m is the slope.

b is the y-intercept, the value of y when x=0.

2x-y=9

Let's subtract 2x from both sides...

-2x+2x-y=9-2x

-y=-2x+9

Let's multiply both sides by -1...

-1(-y)=-1(-2x+9)

y=2x-9

m=2

b=-9

Answer 2

Convert the equation to its equivalent y = 2x-9 (add y+9 to both sides).  Since we KNOW, ABSOLUTELY, that a straight line equation is in the form of y = (slope)*x + y-intercept ... the slope is 2 and the y-intercept is -9.