Question

I have these two points, (7,3) and (8,5). I solved on Mathway and got y = 2x + 11. Can someone explain how I can find that?

Answer 1

@thomaster

Answer 2

@Hero

Answer 3

Explain what you did to solve it on mathway.

Answer 4

I gave the engine the two points, and pressed "Find the equation using Point-Slope"

Answer 5

I've been stuck on this problem for a while and resulted to this

Answer 6

I solved my first problem using point - slope, and it worked fine, I'm not sure why this one is giving me trouble.

Answer 7

\(\bf \begin{array}{lllll}
&x_1&y_1&x_2&y_2\\
&({\color{red}{ 7}}\quad ,&{\color{blue}{ 3}})\quad &({\color{red}{ 8}}\quad ,&{\color{blue}{ 5}})
\end{array}
\\\quad \\

slope = {\color{green}{ m}}= \cfrac{rise}{run} \implies \cfrac{{\color{blue}{ y_2}}-{\color{blue}{ y_1}}}{{\color{red}{ x_2}}-{\color{red}{ x_1}}}
\\ \quad \\

y-{\color{blue}{ y_1}}={\color{green}{ m}}(x-{\color{red}{ x_1}})\qquad \textit{plug in the values and solve for "y"}\\
\qquad \uparrow\\
\textit{point-slope form}\)

Answer 8

I know, I have the slope already

Answer 9

The slope is 2

Answer 10

ok... so plug it in and solve for "y" then :)

Answer 11

That's what I'm having trouble with

Answer 12

I haven't been getting y = 2x + 11

Answer 13

Which is why I've come to you guys for help

Answer 14

that is correct \(\bf y-{\color{blue}{ 3}}={\color{green}{ 2}}(x-{\color{red}{ 7}})\implies y-3=2x-14\implies y=2x-14+3\)

Answer 15

Wouldn't you get y = 2x - 17?

Answer 16

@jdoe0001 he solved it on mathway but couldn't figure out how to solve it on his own.

Answer 17

well... "he" didn't "solve" it in mathway
mathway simply gave the answer heehe

Answer 18

I do know how to solve it, but I just can't understand why I'm getting it wrong

Answer 19

I use mathway sometimes to check my answer when I'm uncertain of my own

Answer 20

well..... look at => \(\bf y-{\color{blue}{ 3}}={\color{green}{ 2}}(x-{\color{red}{ 7}})\implies y-3=2x-14\implies y=2x-14+3\)

anything you find wrong there?

Answer 21

superhelp101 that sounds fair :)

Answer 22

:>

Answer 23

But no, I don't see anything wrong

Answer 24

Oh, wait a second

Answer 25

Nevermind

Answer 26

lol

Answer 27

I think you got -17 because you didn't add \(\bf +3\) you subtracted \(\bf -3\) to both sides

and to eliminate it from the left side, you have to add it

Answer 28

No, I added it to both sides

Answer 29

Let me show you how I've been solving it

Answer 30

k

Answer 31

y - 3 = 2(x - 7)
y + 3= 2(x - 7 + 3)
y = 2x - 10

Answer 32

Dangit, forgot to do the multiplication

Answer 33

y = 2x - 17***

Answer 34

?

Answer 35

The second one is my answer

Answer 36

y - 3 = 2(x - 7)
y + 3= 2(x - 7 + 3) <------ \(\Large ?\)

Answer 37

yes.. but how did you get it?

Answer 38

I showed up above, but here it is again.
y - 3 = 2(x - 7)
y + 3= 2(x - 7 + 3)
y = 2x - 10

Answer 39

You see I don't get it either.