Solve the simultaneous equations: y-2x-4=0, 4x^2+y^2+20x=0

Re-arrange y-2x-4=0 to y=2x+4Substitute y=2x+4 into 4x^2+y^2+20x=0 to get 4x^2+(2x+4)^2+20x=0Expand the brackets to get 4x^2+(4x^2+16x+16)+20x=0Simplify to get 8x^2+36x+16=0Divide by 4 to get 2x^2+9x+4=0Factorise to get (2x+1)(x+4)=0Set each bracket to zero so that x= -1/2 or -4Plug these values back into y=2x+4 to get y= 3 or -4