Question

Halla el valor numérico de:

a) x2 +x−2 parax=3.
b) 2π r para r = 2.
c) x3 −3x2y+3xy2 −y3 parax=2ey=-1

Answer 1

$a) {3}^{2} + 3 - 2 = 9 + 3 - 2 = 12 - 2 = 10$

$b)2 \times \pi \times 2 = 4\pi$

$c) {2}^{3} - 3 \times {2}^{2} \times ( - 1) + 3 \times 2 \times {( - 1)}^{2} - {( - 1)}^{3} = \\ 8 - 3 \times 4 \times ( - 1) + 3 \times 2 \times 1 - ( - 1) = \\ 8 - 12 \times ( - 1) + 6 \times 1 - ( - 1) = \\ 8 - ( - 12) + 6 - ( - 1) = \\ 8 + 12 + 6 + 1 = \\ 20 + 6 + 1 = \\ 26 + 1 = \\ 27$