Question

what should be the value of a if the value of 3x²+5x+a is-2for x=-2?

Answer 1

Given x = -2
$= 3 {x}^{2} + 5x + a = - 2 \\ = 3 ( { - 2}^{2} ) + 5( - 2) + a \: = - 2 \\ = 3(4) + ( - 10) + a \: = - 2 \\ = 12 - 10 + a = - 2 \\ = \: \: \: \: \: \: \: \: 2 \: \: \: + a \: = - 2 \\ = \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: a \: = - 2 - 2 \\ = \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: a \: = \: - 4$