Question

-7x - 4y = 23
2x + 8y = 14
solve by elimination.

Answer 1

2x + 8y = 14
x+4y=7
x = 7 - 4y

Answer 2

plug that into the first equation:
-7(7-4y)-4y=23
-49+28y-4y=23

Answer 3

why do u have x + 4y = 7

Answer 4

Divide everything in the 2nd equation by 2

Answer 5

and then after u plug it, that's when i get confused

Answer 6

-7(7-4y)-4y=23
-7*7+(-7)*(-4y)-4y=23

Answer 7

-49 + 28y - 4y = 23

Answer 8

hold up, i think i got it:) thank you! i have 2 mrore questions, if you have time.

Answer 9

more*

Answer 10

24y = 12x - 24
8x = 16y + 16

Answer 11

look at the 2nd equation, divide everything by 8:
x = 2y+2

Answer 12

\[-7x-4y=23\]
\[2x+8y=14\]
We should be able to get at least one number common in both equations to eliminate it, so multiply 1st equation by -2 to get 8y in both equation one and two, so we have:
\[14x+8y=-46\]
\[2x+8y=14\]
Cancel out 8y so, we have;
\[14x-2x=-46-14\]
\[12x=-60\]
\[x=-60/12\]
\[x=-5\]
Substitute the value of x in any of the two equations to find y:
\[2(-5)+8y=14\]
8y=14+10
8y=24
y=24/8=3
y=3
So, x=-5 and y=3

Answer 13

okay, and what should i do next? :)

Answer 14

24y = 12x - 24
8x = 16y + 16

look at the 2nd equation, divide everything by 8:
x = 2y+2
Divide the first equation by 12:
2y = x - 2
Plug the value of x from the 2nd equation into the first one:
2y = 2y+2-2
0=0
Those are both the same line, an infinite number of solutions exists

Answer 15

go go go bahrom! lol

Answer 16

oh okayy! :) & last one;
0 = -24 - 24y + 16x
2 - y = -x

Answer 17

divide the top one by 4:
0 = -6 - 6y +4x
multiply everything by -1 in the 2nd equation:
-2+y=x, or x = y-2
Plug that into the first equation:
0 = -6 - 6y +4x
0 = -6 - 6y +4(y-2)
0 = -6 - 6y +4y-8
0 = -6-8-6y+4y
0=-14-2y
add 14 to both sides:
14 = -2y
divide both sides by -2:
14/-2 = y
-7=y, or y = -7

Answer 18

x = y-2
x = -7-2=-9

Answer 19

thank you!!!!