Simplify the polynomial. −3x2+6+2x−5x+4x2+9 (1 point) Responses −x2+3x+15 negative x squared plus 3 x plus 15 7x2+3x+3 7 x squared plus 3 x plus 3 x2−3x+15 x squared minus 3 x plus 15 −x2+7x+15

x^2 + 3x + 15