Answer:
y=-5x-6
Step-by-step explanation:
Parallel means you are looking for an equation that has the same slope as the one given.
The slope of y=-5x+9 is -5.
All I did was compare it to y=mx+b where m is slope and b is y-intercept.
So our equation is in the form y=-5x+b.
We want to find b such that y=-5x+b goes through (3,-21).
So we can plug in our point that is on this line so that that happens.
-21=-5(3)+b
-21=-15+b
Add 15 on both sides
-6=b
b=-6
So the line that is parallel to y=-5x+9 while going through (3,-21) is y=-5x-6.
