Question

solve the quadratic equation 84x^2 + 16x = 0 by factoring out the GCF
the solution set is x={0, 4/21}
the solution set is x-{0, 4}
the solution set is x={-4/21, 0}
the solution set is x={-4, -4/21}

Answer 1

84x^2 + 16x = 0
Factor out the GCF 4x: 4x(21x + 4) = 0
Set each factor to zero:
4x = 0 → x = 0
21x + 4 = 0 → x = -4/21

So the solution set is {0, -4/21}. That corresponds to the option "x = {-4/21, 0}".