(5+2х)^2-2,5х(8х+7) х=-0,5

Question

(5+2х)^2-2,5х(8х+7) х=-0,5

Answer 1

(5+2х)²-2,5х(8х+7)=25+20х+4х²-20х²-17,5х=25+2,5х-16х²,
если х=-0,5, то 25+2,5·(-0,5)-16·(-0,5)²=25-1,25-16·0,5²=19,75.
Ответ: 19,75.