Esercizio 225
5x(x-1) -2(x-1)^2 +(x-2)(x+3)=4x^2 -10x -18
5x^2 -5x -2x^2 -2 +4x +x^2 +x-6 -4x^2 +10x +18=0
-5x -2 +4x+x-6 +10x +18=0
10x = -10 ; x=-1
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5x*(x-1) - 2*(x-1)^2 + (x-2)*(x+3) = 4x^2 - 10x - 18
5x^2 - 5x - 2x^2 - 2 + 4x + x^2 + x - 6 - 4x^2 + 10x = -18
-5x - 2 + 4x + x - 6 +10x + 18 = 0
10 x = -10
x = -1
225)
$\small \dfrac{x(x-1)}{2}-\dfrac{(x-1)^2}{5}+\dfrac{(x-2)(x+3)}{10} = \dfrac{2}{5}x^2-x-\dfrac{9}{5}$ $\quad\small [mcm=10]$
$\small 5x(x-1)-2(x-1)^2+(x-2)(x+3) = 4x^2-10x-18$
$\small 5x^2-5x-2(x^2-2x+1)+x^2+3x-2x-6 = 4x^2-10x-18$
$\small 5x^2-\cancel{5x}-2x^2+\cancel{4x}-2+x^2+\cancel{x}-6 = 4x^2-10x-18$
$\small 4x^2-8 = 4x^2-10x-18$
$\small \cancel{4x^2}-\cancel{4x^2}+10x = -18+8$
$\small 10x = -10$
$\small \dfrac{\cancel{10}x}{\cancel{10}} = \dfrac{-10}{10}$
$\small x = -1$