(5x+3y)²-(2x-y)(4x-9y)
Ответ:
(5x + 3)²- (2x - y)(4x-9y)
(8x)²-(8x²-6xy-4xy+3y²)
64x²-(8x²-6xy - 4xy+3y²)
64x²-(8x²-10xy+3y²)
64x²-8x²+10xy-3y²
64x²-8x²
(64 - 8)x²=56²
56x²+10xy-3y²