Solve the simultaneous equation: y+4x+1=0 y^2+5x^2+2x=0

Rearrange the first equation to get y on its own:   y=-(1+4x) Substitute into the second equation:        (1+4x)(1+4x)+5x^2+2x=0     21x^2+10x+1=0 Substite into the quadratic formula to solve    (-b+/-(b^2-4ac)^0.5)/2a