To solve the system of equations, which expression could be substituted for x into the first equation?

Question

3x-5y=14
x+4y=10

a)10-4y
b)4y+10
c)(1/4)x+(5/2)
d)(-1/4)x+(5/2)

I have another problem just like this one so if you could explain how to solve this one I can (hopefully) solve the other,thanks

Solve the second equation for x:

x + 4 y = 10 --->

x = 10 - 4 y

ok I think I got the idea,lets try this one.

2x+7y=10
x-2y=15

I'm thinking 2y-15 here are the choices:
a)(1/2)x+15
b)(1/2)x-15
c)2y+15
d)2y-15

x-2y=15 ---->

x = 2y + 15

Answer 1

to solve the system of equations, whcih expression could be substituted for x into the first equation? First - 2x+7y=10; second = x-2y=15

Answer 2

wait, so you use reverse Order of Operations to solve x - 2y = 15, right?
Im in 7th grade and i still dont really know how to do this type of math...