Question

Please help me! I will give a medal!
Choose the equation of the line passing through the point (-3, 1) and parallel to y = -x - 4.

y = x + 2
y = -x - 2
y = -x + 4
y = x - 4

Answer 1

Hint: Parallel lines have _____ slopes ...?

Answer 2

well, identical....

Answer 3

Right, So we know the line we will have will also have a slope of -1

So automatically we are down to either B or C

Answer 4

-1? doesn't it say -2?

Answer 5

Not quite...the line we are given is

\[\large y = -x - 4\]

if we compare that to slope intercept form...

\[\large y = mx + b\]

'm' is our slope there...which is -1

Answer 6

Does that make sense?

Answer 7

Now, the line must pass through the point (-3,1) ...since we know the slope is to be -1...we can plug that slope and that point into the formula \(\large y = mx + b\) to solve for 'b' (our y-intercept)

So we have

\[\large 1 = (-1)(-3) + b\]

and solve that for 'b'

Answer 8

I don't understand how i would solve for b though.

Answer 9

because wouldn't you have to do everything on both sides..?

Answer 10

Well lets see..

\[\large 1 = (-1)(-3) + b\]

What is -1 times -3? it is 3 ...so we have

\[\large 1 = 3 + b\]

Now we want to solve for 'b'...so subtract 3 from both sides of the equation
\[\large b = -2\]

Answer 11

ooooh! ok that makes a lot more sense now, because i didn't know that i had to multiply those two negatives first.

Answer 12

What we now have...is the y-intercept of the line we wanted...so now...we can write what the equation of the parallel line is...

\[\large y = -x - 2\]

Answer 13

thank you so much! it totally makes sense now, you are awesome!

Answer 14

No problem :)