Question

Solve the system algebraically

2x+y-10=0
X-y-4=0

What is the value of y?

A) 1/3
B) 2/3
C) 14/3

Answer 1

2x+y-10 = 0
x - y - 4 = 0
===========
3x - 14 = 0

3x = 14
x = 14/3

x - y = 4
14/3 - y = 4
14/3 - 4 = y
14/3 - 12/3 = y
2/3 = y

y = 2/3

or

Multiply the second equation by 2 and then subtract the new one from the first one. We get 3y -2 = 0, so y = 2/3.
Hence the value of y is 2/3.

Depends which way you like to solve it...