Math, asked by hii5061, 3 months ago

factorise using
(x+a)(x+b)=x²+(a+b)x+ab

(I) x²+14x+45
(ii) x²-22x +120
(iii) y²+5y-36
(iv)a²+3a-88
(v)x²-4x-21

Answers

Answered by harshitha926594
7

Answer:

i) \:  \:  \:  {x}^{2}  + 14x + 45 \\   \:  \:  \: {x}^{2}  + 9x + 5x + 45 \\  \:  \:  \: x(x + 9) + 5(x + 9) \\  \:  \:  \: (x + 9)(x + 5) \\   \\  ii) \:  \:  \:  {x}^{2}  + 22x + 120 \\  \:  \:  \:  {x}^{2}  + 10x + 12x + 120 \\  \:  \:  \:  x(x + 10) + 12(x + 10) \\  \:  \:  \: (x + 10)(x + 12) \\  \\ iii) \:  \:  \:  {y}^{2}  + 5y - 36 \\  \:  \:  \:  {y}^{2}  + 9x - 4x - 36 \\  \:  \:  \: y(y + 9) - 4(y + 9) \\  \:  \:  \: (y + 9)(y - 4) \\  \\ iv) \:  \:  \:  {a}^{2}  + 3a - 88 \\  \:  \:  \:  {a}^{2}  + 11a - 8a - 88 \\ \:  \:  \:  a(a + 11) - 8(a + 11) \\ \:  \:  \:  (a + 11)(a - 8) \\  \\ v) \:  \:  \:  {x}^{2}  - 4x - 21 \\  \:  \:  \:  {x}^{2}  - 7x + 3x - 21 \\  \:  \:  \: x(x - 7) + 3(x - 7) \\  \:  \:  \: (x - 7)(x + 3)

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