а) (5+2х)(2х-5)+25=10х-25+4х²-10х+25=4х²
b) 4(7-2а)-(а-4)²=28-8а-(а²-8а+16)=28-8а-а²+8а-12=-а²+12(×-1)=а²-12
б) 4(7-2а)-(а-4)²= 28-8а-(а²-8а+16)=28-8а-а²+8а-16=-а²+12
а) (5+2х)(2х-5)+25=10х-25+4х²-10х+25=4х²
b) 4(7-2а)-(а-4)²=28-8а-(а²-8а+16)=28-8а-а²+8а-12=-а²+12(×-1)=а²-12