Разложите на множители 49-(5d+3)²
49-(5d+3)²=7²-(5d+3)²=(7-(5d+3))(7+(5d+3))=(7-5d-3)(7+5d+3)=(4-5d)(10+5d)
49-(25d^2 +30d+9) 49-25d^2-30d-9