Question

(5-2x)(5+2x)-(3-2x)(4-2x)

Answer 1

(5-2x)(5+2x)-(3-2x)(4-2x)=5²-(2х)²-(12-6х-8х+4х²) = 25-4х²-12+6х+8х-4х²=-8х²+14х+13