Question

help please
x+7y=39
3x-2y=2
solve using substitution

Answer 1

@iGreen can u help me please

Answer 2

Subtract 7y to both sides:

x + 7y = 39

x = -7y + 39

Distribute -7y + 39 for 'x' in the 2nd equation:

3x - 2y = 2

3(-7y + 39) - 2y = 2

Distribute 3 into the parenthesis:

-21y + 117 - 2y = 2

Combine like terms, what's -21y - 2y?

Answer 3

-23?

Answer 4

-23y, yes.

So we have:

-23y + 117 = 2

Subtract 117 to both sides, what's 2 - 117?

Answer 5

-115? can u please tell me how u got 117 in the first place

Answer 6

I distributed 3 into the parenthesis..

3 * -7y = -21y
3 * 39 = 117

Answer 7

Anyway, we have:

-23y = -115

Divide -23 to both sides, what's -115 / -23?

Answer 8

oh okay I understand now.. y=5?

Answer 9

Yep, you got it..

Now we plug it into any of the two equations to get the 'x-value'.

x + 7y = 39

x + 7(5) = 39

Simplify & Solve for 'x'

Answer 10

a little stuck got x=38?

Answer 11

No..what's 7 * 5?

Answer 12

nevermind I had 3 at the end and not 39... 7*5=35 I got that part

Answer 13

Yes, so we have:

x + 35 = 39

Subtract 35 to both sides

Answer 14

so the final answer is (4,5)?

Answer 15

Yep, you got it.

Answer 16

thanks

Answer 17

x+7y=39
x=39-7y------(1)
3x-2y=2
3(39-7y)-2y=2
117-21y-2y=2
117-23y=2
117-2=23y
115=23y
y=115\23
y=5
3x-2(5)=2
3x-10=2
3x=12
x=4

Answer 18

yup that's what I got thanks @sangineni