Question

If the slope of the line that passes through the points (a,0) and (1,-2) is 1/2, what is the value of a? @jim_thompson5910

Answer 1

have you applied the slope formula?

Answer 2

\[m=\frac{y_2-y_1}{x_2-x_1} \]

Answer 3

No. I do not know that to do that with this problem.

Answer 4

well you are given two points on a line and the slope ... which makes me think slope formula since only one of the values is unknown in the pairs given

you are given m is 1/2
(x1,y1)=(1,-2)
and
(x2,y2)=(a,0)

Answer 5

\[\frac{1}{2}=\frac{0-(-2)}{a-1}\]
solve for a

Answer 6

a = -2

Answer 7

how did you get that?

Answer 8

0 + 2 is 2 and a - 1 is -1

Answer 9

it might make it easier on you if you flip both sides
\[\frac{2}{1}=\frac{a-1}{0-(-2)}\]
see if you can solve now

Answer 10

by the way 2/1 is just 2

Answer 11

\(\bf \begin{array}{lllll}
&x_1&y_1&x_2&y_2\\
% (a,b)
&({\color{red}{ a}}\quad ,&{\color{blue}{ 0}})\quad
% (c,d)
&({\color{red}{ 1}}\quad ,&{\color{blue}{ -2}})
\end{array}
\\\quad \\
% slope = m
slope = {\color{green}{ m}}= \cfrac{rise}{run} \implies
\cfrac{{\color{blue}{ y_2}}-{\color{blue}{ y_1}}}{{\color{red}{ x_2}}-{\color{red}{ x_1}}}\implies
\cfrac{{\color{blue}{ -2}}-{\color{blue}{ 0}}}{{\color{red}{ 1}}-{\color{red}{ a}}}=\cfrac{1}{2}\)

Answer 12

I am confused now.

Answer 13

confused on how to solve 2=(a-1)/2 for a?

Answer 14

Yes.

Answer 15

are confused on the flipping part?
confused on the equation we got?

Answer 16

I am confused on solving with A.

Answer 17

solving with A?

Answer 18

what does that mean

Answer 19

you mean solve for a?

Answer 20

The variable is A in the equation

Answer 21

don't we have a not A?
\[\frac{1}{2}=\frac{0-(-2)}{a-1} \\ \\ 0-(-2) \text{ is the same as } 2 \\ \text{ you have } \\ \frac{1}{2}=\frac{2}{a-1}\]

Answer 22

you can flip both sides like I did earlier

\[\frac{2}{1}=\frac{a-1}{2} \\ \text{ now } \frac{2}{1}=2 \\ 2=\frac{a-1}{2}\]

Answer 23

try to undo that division by 2 ...multiply 2 on both sides

Answer 24

1=4/a-1?

Answer 25

well 2 times 2 is 4 not 1
and how did you put a-1 back in the denominator?
also 2/2=1 not 4...

Answer 26

oh you went backwards

Answer 27

it is 1/2 times 2

Answer 28

do you see this equation
2=(a-1)/2

I was asking you multiply this equation by 2 on both sides

Answer 29

this gives you 4=a-1

Answer 30

how did you get 2?

Answer 31

@Jhannybean you can finish
i have to leave I'm sorry

Answer 32

I get it now.

Answer 33

\[2=\frac{a-1}{2} \implies 4 = a-1 \implies a= 4+1\]

Answer 34

That is what I got.

Answer 35

Thank you.