Question

In the below system, solve for y in the first equation.

3x + y = 9
4x – 3y = 6

Answer 1

y = 9 - 3x

Answer 2

how'd you get that?

Answer 3

subtract 3x from both sides

Answer 4

Can you draw it so I can see what your talking about?

Answer 5

Actually, if this is a system of equations, bob's answer isn't completely correct.

What you want to do is solve for x in the first equation:

3x + y = 9 ---> 3x = 9 - y ---> x = (9-y)/3


now plug this value into your second equation:
--> 4[(9-y)/3] - 3y = 6 (plugged x = (9-y)/3 in for x)

and solve for y:
4*(9/3 - y/3) - 3y = 6
36/3 - 4y/3 - 3y = 6 (distributed the 4)
4y/3 - 3y = 6 - 12 (simplified 36/3 and took it to the other side)
4y - 9y = 18 - 36 (multiplied everything by 3 to make things simpler)
-5y = -18 (divide by -5)
y = -18/-5
y = 18/5 or 3.6


so remember: solve for one of the variables in the first equation then plug it into the second equation to get your answer

Answer 6

Thank you!!! <3

Answer 7

ur welcome :)