Câu hỏi của N cn

Question

Tìm x

x (2x -1) (x+5) - (2x2+1) (x+4.5) = 3.5

lê thị hương giang · Accepted Answer

$x\left(2x-1\right)\left(x+5\right)-\left(2x^2+1\right)\left(x+4,5\right)=3,5$

$\Rightarrow\left(2x^2-x\right)\left(x+5\right)-2x^3-9x^2-x-4,5=3,5$

$\Rightarrow2x^3+10x^2-x^2-5x-2x^3-9x^2-x-4,5=3,5$

$\Rightarrow-5x-4,5=3,5$

$\Rightarrow-5x=8$

$\Rightarrow x=-\dfrac{8}{5}$Câu trả lời: $x\left(2x-1\right)\left(x+5\right)-\left(2x^2+1\right)\left(x+4,5\right)=3,5$

$\Rightarrow\left(2x^2-x\right)\left(x+5\right)-2x^3-9x^2-x-4,5=3,5$

$\Rightarrow2x^3+10x^2-x^2-5x-2x^3-9x^2-x-4,5=3,5$

$\Rightarrow-5x-4,5=3,5$

$\Rightarrow-5x=8$

$\Rightarrow x=-\dfrac{8}{5}$