(5x+2)(x+10)+(5x–2)(x–10)x2−100 —————————————————- (x-10)(x+10)

Đáp án:

Giải thích các bước giải:

$\frac{\left( 5x+2 \right)\left( x+10 \right)+\left( 5x-2 \right)\left( x-10 \right).2-100}{\left( x-10 \right)\left( x+10 \right)}$

$=\frac{5{{x}^{2}}+50x+2x+20+\left( 5{{x}^{2}}-50x-2x+20 \right).2-100}{{{x}^{2}}-100}$

$=\frac{5{{x}^{2}}+52x+20+10{{x}^{2}}-100x-4x+40-100}{{{x}^{2}}-100}$

$=\frac{15{{x}^{2}}-52x-40}{{{x}^{2}}-100}$