2x²/(x-1) -3x/(x+2) =2(4x-1)/(x² +x-2) ;* * * ОДЗ : x≠ -2 и x≠1 * * *
(<u>2x² -2 </u>+2)/(x-1) -(<u>3x+6</u> -6)/(x+2) =2(4x-1)/(x² +x-2) ;
2(x² -1)/(x-1) +2/(x-1) -3(x+2)/(x+2) +6/(x+2) =2(4x-1)/(x² +x-2) ;
2(x+1) -3 +2/(x-1) +6/(x+2) =2(4x-1)/(x² +x-2) ;
2(x+1) -3 + <u>(2(x+2)+6(x-1))/(x-1)(x+2)</u> =2(4x-1)/(x² +x-2) ;
2(x+1) -3 + 2(4x-1)/(x² +x-2) =2(4x-1)/(x² +x-2) ;
2(x+1) -3 =0 ;
2x+2 -3 =0 ;
x=1/2.
Из ф-лы (a+b)²=a²+2ab+b² следует
4x²+16xy+16y²=(2x+4y)²
значит
4x"+6x+16xy+12y+16y"=(2x+4y)²+6x+12y
<span>Зная, что 2x+4y=23
</span>23²+3*23=26*23=598