Question

Упростите выражение и найдите его значенин: а) x(2x-2y)+x(2y-x)-2(x-y^2); x=-0,1, y=0,7
Б) 5v(2v^2-v+3)-4v(v^2-2v+5)-6v(v^2+ 1/2v-4); v= -7/19​

Answer 1

$\displaystyle\bf\\1)\\\\x(2x-2y)+x(2y-x)-2(x-y^{2} )=\\\\=2x^{2} -2xy+2xy-x^{2} -2x+2y^{2} =x^{2} -2x+2y^{2} \\\\x=-0,1 \ \ ; \ \ y=0,7\\\\x^{2} -2x+2y^{2}=(-0,1)^{2} -2\cdot(-0,1)+2\cdot0,7^{2} =\\\\=0,01+0,2+0,98=1,19$

$\displaystyle\bf\\2)\\\\5v(2v^{2} -v+3)-4v(v^{2} -2v+5)-6v(v^{2} +\frac{1}{2} v-4)=\\\\=10v^{3} -5v^{2} +15v-4v^{3} +8v^{2} -20v-6v^{3} -3v^{2} +24v=\\\\=19v\\\\v=-\frac{7}{19} \\\\19v=19\cdot\Big(-\frac{7}{19} \Big)=-7$