Question

Resolve into factors:
1) 8x² + 2xy - 15y
2) x^4 - 4x^3 - 21x^2

Answer 1

Answer:

Correct question :-

1) 8x² + 2xy - 15y²

Solution :-

➪ 8x² + 2xy - 15y²

➭ 8x² + (12 - 10)xy - 15y²

➭ 8x² + 12xy - 10xy - 15y²

➭ 4x(2x + 3y) - 5y(2x + 3y)

➭ (2x + 3y) (4x - 5y)

∴ The value of 8x² + 2xy - 15y² is

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

Question :-

2) x⁴ - 4x³ - 21x²

Solution :-

➪ x⁴ - 4x³ - 21x²

➭ x²(x² - 4x - 21)

➭ x² {x² - (7 - 3)x - 21}

➭ x² {x² - 7x + 3x - 21}

➭ x² {x(x - 7) + 3(x - 7)}

➭ x² {(x - 7) (x + 3)}

➭ x²(x - 7) (x + 3)

∴ The value of x⁴ - 4x³ - 21x² is

x²(x - 7) (x + 3)