Which equation can be used to solve the following system? x+y=11
4x^2-3y^2=8

Rearrange x + y = 11.
x = 11 - y
Substitute into other equation.
4(11 - y)^2 = 3y^2 = 8
Answer:
4(11 - y)^2 - 3y^2 = 8 (#2)