Question

F'(x)=(x^2+3x)'×(x^4)'

Answer 1

$4x {}^{3} (x {}^{2} + 3x) + {x}^{4} (2x + 3) = 4 {x}^{5} + 12 {x}^{4} + 2 {x}^{5} + 3 {x}^{4} = 3 {x}^{4} (2x + 5)$