Question

Complete the equation for the linear function whose graph contains the point
(−1, 2) and has a slope of 0.9.

y =____x + ____

i imagine it would start like y = 0.9x + ____

maybe y = 0.9x + 2 ??

Answer 1

You are very close!

The slope is as you say 0.9. It means that if you increase x by 1, you increase y by 0.9.

However, if y = 0.9x + 2, then what happens if you plug in x = -1. You do not get 2, but rather
y = 0.9*(-1) + 2 = 1.1.

Answer 2

Therefore, + 2 cannot be right. You should have gotten 2, since the line was supposed to go through (-1,2)

Answer 3

that makes sense, but then how do i figure out what goes in that space?

Answer 4

what number*

Answer 5

Ok, good.

Well, what if we say that the right number is a, so that
y = 0.9*x + a
You know that y = 2 at x = -1

Answer 6

If you solve for a, then you get the constant term :)

Answer 7

okay let me do that, and see what i get

Answer 8

the slope intercept form of the line is

\[y = mx + b\]

m = slope which you know and b = y- intercept

so your line is

\[y = 0.9x + b\]

to find the value of b, use the point x = -1 and y = 2

substitute them and solve for b

Answer 9

Could not agree more, campbell_st :)

Answer 10

hmm okay i got

2 = 0.9 x -1 + 2.9

Answer 11

correct

Answer 12

so now you know b... and have the equation of the line

Answer 13

can you help with another one @SfunnSneffanS ?

Answer 14

Sure :)