(1) x + y = 2(2) 4y2 - x2 = 11
Rearrange (1) to x= 2-y & substitute x=2-y into equation (2)
Simplify the new equation to 3y2+4y-15 = 0, use quadratic formula or simplify to (3y-5)(y+3)=0 and solve to get
y1= 5/3 y2 = -3
Substitute the values of y1 and y2 into equation one and solve for the 2 values of x
y1= 5/3 x1= 1/3 y2 = -3 x2 = 5
Substitute answers for x and y back into the original equations to verify they are correct