What is the equation of a line that passes through (7, 8) and has a slope of -3?

Question

i need the correct answer

 

Answer 1

Hello Sierra,

The equation for the Slope Intercept Form: 

y = m(x) + b 

You are provided several important pieces of information in your problem: you are given the slope and a pair of coordinates (7,8), right? 

Therefore: 

y = (-3)x + b 

Now you can plug your coordinates (7,8) into that equation. 

8 = (-3)7 + b 

Solve for b

8 = -21 + b

Add +21 to both sides of your equation:

29 = b

Now, your new equation is: 

y = -3x + 29 


I hope this assists. 

Answer 2

First equation of could be  written in the form y=ax+b. In you question a=-3. You have to find b. How?

You have y=-3x+b. This lines passes through (7,8). This means when x=7, y=8

So.

8=-3(7)+b.

b=29.

Equation of line is y=-3x+29.