(8x+31)/(x+7)+9/(x-1)<0<br>(8x²+31x-8x-31+9x+63)/(x+7)(x-1)<0<br>(8x²+32x+32)/(x+7)(x-1)<0<br>8(x²+4x+4)/(x+7)(x-1)<0<br>8(x+2)²/(x+7)(x-1)<0<br>x=-2 x=-7 x=1
+ _ _ +
-------------(-7)-------------(-2)-----------------(1)-------------------
x∈(-7;-2) U (-2;1)