Question

System of equation: substitution method
8x+3y=26
2x=y-4

Answer 1

\[x = \frac{ y }{ 2 } - 2\]
\[8(\frac{ y }{ 2 } - 2) + 3y = 26\]
\[4y - 16 + 3y = 26\]
\[7y - 16 = 26\]
\[7y = 44\]
\[y = 6.29\]

Are you supposed to have a decimal? If not, y = 10
hehe

Answer 2

no your trying to find x and y for cordinates

Answer 3

x = 7

Answer 4

how did u get 7 all i see is the y

Answer 5

or...
2x = y - 4
2x + 4 = y
now sub 2x + 4 in for y in the 1st equation

8x + 3y = 26
8x + 3(2x + 4) = 26
8x + 6x + 12 = 26
14x = 26 - 12
14x = 14
x = 1

now sub 1 in for x in either of the original equations
2x = y - 4
2(1) = y - 4
2 = y - 4
2 + 4 = y
6 = y

now lets check...
8x + 3y = 26
8(1) + 3(6) = 26
8 + 18 = 26
26 = 26 (correct)

x = 1 and y = 6

Answer 6

Well, using a different method, I got x = 7, y = 10. I'm not that good with this method, can anyone else correct me.

Answer 7

any questions ?

Answer 8

...I keep doing the wrong variable first...

Answer 9

it doesn't matter which variable you do first

Answer 10

Well, can you solve for x first?

Answer 11

I did y first because it was already by itself

Answer 12

2x = y - 4
x = (y - 4)/2
x = 1/2y - 2

now sub 1/2y - 2 in for x
8x + 3y = 26
8(1/2y - 2) + 3y = 26
4y - 16 + 3y = 26
7y = 26 + 16
7y = 42
y = 6

now sub 6 in for y
2x = y - 4
2x = 6 - 4
2x = 2
x = 1

Answer 13

it does not matter which variable you solve for first, as you can see, you will get the same answer

Answer 14

i just wanna check if i got it right
x-7y=13
3x-5y=23 for this equation i got {6,-1}

Answer 15

x - 7y = 13 --> x = 7y + 13
3x - 5y = 23
3(7y + 13) - 5y = 23
21y + 39 - 5y = 23
16y = -16
y = -1

x - 7y = 13
x -7(-1) = 13
x + 7 = 13
x = 13 - 7
x = 6

you are correct :)

if your ever in doubt, you can check you answers by subbing them back into the equations.
3x - 5y = 23
3(6) - 5(-1) = 23
18 + 5 = 23
23 = 23 (correct)
if they come out equal, then your answers are correct....if they don't come out equal, then there is a problem.

Answer 16

can you use any of both equations to double check

Answer 17

you can use either one or both

Answer 18

okay thank you :)

Answer 19

your very welcome :)