Question

Write the equation of the line that passes through (3, 4) and (2, –1) in slope-intercept form.

A.y = 3x – 7
B. y = 3x – 5
C.y = 5x – 11
D. y = 5x – 9

Answer 1

Slope formula:

\(\huge{Slope=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}}\)

Plug in...

\(\huge{Slope=\frac{-1-4}{2-3}}\)

Answer 2

So would it be B?

Answer 3

Not quite. We need to find slope once we do we plug it into the slope-intercept formula....

\(\huge{y=mx+b}\)

\(\Large{m=slope}\)
\(\Large{b=y-intercept}\)

~~~~~~~~~~~~~~~~~~~~~~~~~~

\(\huge{Slope=\frac{-5}{-1}=5}\)

~~~~~~
\(\Huge{y=5x+b}\)
We would now find b so we would input a set of points into y and x....lets use (3,4)...

\(\huge{4=5(3)+b}\)

Answer 4

What would b equal?

Answer 5

y?

Answer 6

To find b we would need to input a set of points into the open `y` and `x`....We will use `(3,4)` for this....

\(\huge{y=5x+b \rightarrow 4=5(3)+b}\)

We have our original equation in which we apply the points...We now would simplify....

\(\huge{4=5(3)+b \rightarrow 4=15+b}\)

We would then subtract `15` to the other side...

\(\huge{(4-15=(15-15)+b \rightarrow~ ?}\)

What would that equal?

Answer 7

11

Answer 8

?

Answer 9

Correct :D

Now we would input 11 as b and get our final equation...

\(\Huge\color{red}{y=5x-11}\)

Answer 10

thank you!

Answer 11

np :D