Question

o valor da expressao 3a² - 5ab,sendo A = 3 e b = -2, é?

Answer 1

$3{a}^{2} - 5ab = 3 \times {3}^{2} - 5 \times 3 \times ( - 2) = \\ = 3 \times 9 + 30 = 27 + 30 = 57$

Answer 2

3x9-( 5x3x-2)
27-( -30)
27+30= 57