Factorise: x²+14x+45
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To factorise:
x²+14x+45
⟾x²+14+45
⟾x²+(9+5)x+(9)(5)
⟾x²+9x+5x+(9)(5)
⟾x(x+9)+5(x+9)
⟾(x+9)(x+5)
Explanation about the answer:-
The above equation is solved by taking identity:-
(x+a)(x+b)=x²+(a+b)x+ab
There is a constant term 45 that can be factorised as 45= 15 × 3 on 9 × 5.
In this, I considered the factors of 45 whose sum is equal to 14(that is the coefficient of middle term).
Therefore,the factor 15+3 is not suitable as 15+3≠14.
Hence,we have to take the other pair of factors, and i.e., 9+4=14
Thus the required factors of 45 are 9 and 5.
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