(х+7)²-2(х+7)(х-5)²+(х-5)²=х²+14х+49-(2х+14)(х²-10х+25)+х²-10х+25=х²+14х+49-(2х³-20х²+50х+14х²-140х+350)+х²-10х+25=х²+14х+49-2х³+20х²-50х-14х²+140х-350+х²-10х+25=-2х³+8х²+94х-276
-2(3.54)³+8(3.54)²+94(3.54)-276
-2*44.361864+8*12.5316+94*3.54-276
-88.723728+100.2528+332.76-276=68.289072