Question

3) sendo A = 3x2 + 5x -6, determine o valor de A para
a) x = -2
b) x = -1
c) x = 21​

Answer 1

Explicação passo-a-passo:

a)

$\sf A=3\cdot(-2)^2+5\cdot(-2)-6$

$\sf A=3\cdot4-10-6$

$\sf A=12-10-6$

$\sf A=-4$

b)

$\sf A=3\cdot(-1)^2+5\cdot(-1)-6$

$\sf A=3\cdot1-5-6$

$\sf A=3-5-6$

$\sf A=-8$

c)

$\sf A=3\cdot21^2+5\cdot21-6$

$\sf A=3\cdot441+105-6$

$\sf A=1323+105-6$

$\sf A=1422$