Question

Write an equation of the line that passes through (1,2) and is parallel to the line y=−5x+4

Answer 1

We know that the slope is -5, so:

y = -5x + b

Input (1, 2)

2 = -5 + b

b = 7

So:

y = -5x + 7

Answer 2

You are using the equation:

y = mx + b

You need to find "m" and "b".

"m" is the slope, "b" is your y-intercept(when x = 0)

For the equation of the line to be parallel to the given equation, the slopes have to be the SAME. The slope of the given line is -5, so the parallel line's slope is also -5. (m = -5)

y = mx + b

y = -5x + b

To find b, you plug in the point (1,2) into the equation

y = -5x + b

2 = -5(1) + b

2 = -5 + b Add 5 on both sides to get "b" by itself

2 + 5 = -5 + b + 5

7 = b

Your equation is:

y = -5x + 7