7) ($\left$$\frac{1}{7}x-\frac{1}{8}y\right$(7y-8x)+$\left$$\frac{1}{7}y-\frac{1}{8}x\right$(7x-8y))

Question

Вопрос: $Фото задания: 7) ($\left$$\frac{1}{7}x-\frac{1}{8}y\right$(7y-8x)+$\left$$\frac{1}{7}y-\frac{1}{8}x\right$(7x-8y))$ Фото задания

Accepted Answer

Көбейткіштерді ашамыз:

$\left(\frac{x}{7}-\frac{y}{8}\right)(7y-8x)=-\frac{8}{7}x^2+2xy-\frac{7}{8}y^2$.

$\left(\frac{y}{7}-\frac{x}{8}\right)(7x-8y)=-\frac{7}{8}x^2+2xy-\frac{8}{7}y^2$.

Ұқсас мүшелерді біріктіреміз:

$-\left(\frac{8}{7}+\frac{7}{8}\right)x^2+4xy-\left(\frac{7}{8}+\frac{8}{7}\right)y^2=-\frac{113}{56}x^2+4xy-\frac{113}{56}y^2$.

Жауабы: $-\frac{113}{56}x^2+4xy-\frac{113}{56}y^2$.

7) (\(\left\)\(\frac{1}{7}x-\frac{1}{8}y\right\)(7y-8x)+\(\left\)\(\frac{1}{7}y-\frac{1}{8}x\right\)(7x-8y))