Question #85932

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Answer 1 · 2017-03-08T19:24:18

$x = - 1$ $x=-1$ and $x = - \frac{4}{5}$ $x=-4/5$

$5 x^{2} + 9 x = - 4$ $5x^2+9x=-4$

$:.5x+9x+4=0$

$:.(x+1)(5x+4)$

$:.x+1=0$ and $5x+4=0$

$:.color(blue)(x=-1$ and $5x=-4$

$:.color(blue)(x=-1$ and $color(blue)(x=-4/5$

substitute $color(blue)(x=-1$

$:.5(color(blue)(-1))^2+9(color(blue)(-1))=-4$

$:.5(color(blue)(-1))(color(blue)(-1))-9=-4$

$:.5-9=-4$

$:.color(blue)(-4=-4$

substitute $color(blue)(x=-4/5$

$:.5color(blue)((-4/5))^2+9(color(blue)(-4/5))=-4$

$:.5(color(blue)(-4/5))(color(blue)(-4/5))+9(color(blue)(-4/5))=-4$

$:.5(16/25)-(36/5)=-4$

$:.80/25-36/5=-4/1$

$:.(80-180=-100)/25$

$:.color(blue)(-100=-100$