If x-2 is a factor of $5x^2+bx+4$ what is the value of b?

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Answer 1 · 2018-05-02T16:08:14

$b = - 12$

Given;

$5x^2 + bx + 4$

Factor: $x - 2$

Since its a factor therefore;

$x - 2 = 0$

$x = 2$

Substitute the value of $x$ into the main equation..

$5(2)^2 + b(2) + 4 = 0$

$5(4) + 2b + 4 = 0$

$20 + 2b + 4 = 0$

$24 + 2b = 0$

$2b = - 24$

$b = -24/2$

$b = -12$

If x-2 is a factor of 5x^2+bx+45x^2+bx+4 what is the value of b?