Question

simplifiquem as expressões c) (x-3)•(x-5)+ 3x(x+4)

Answer 1

(×-3)×(×-5)+3×(×+4)
2×4+3×5=
8+15=23

Answer 2

$(x^{2} - 5x - 3x + 15) . 3 x^{2} + 12x \\ ( x^{2} - 8x + 15) . 3 x^{2} + 12x \\ 4 x^{2} + 12 x^{3} - 24 x^{3} - 96x + 45 x^{2} + 180x \\ 49 x^{2} - 12 x^{3} + 84x$