1) (2а - 3б ) ² =( 2а)² -2×2а×3б + (3б)² =
4а²-12аб+9б²
2)(5 - а) ( 5 + а ) = 5²- а² = 25 - а²
3) ( 7x +10y)(10y-7x) = (10y)² - (7x)² = 100y² - 49x²
1) (2а - 3б ) ² =( 2а)² -2×2а×3б + (3б)² =
4а²-12аб+9б²
2)(5 - а) ( 5 + а ) = 5²- а² = 25 - а²
3) ( 7x +10y)(10y-7x) = (10y)² - (7x)² = 100y² - 49x²