Question

Factorize :
1. x2(sq) + 18x + 81
4. 9x2 - 24x + 16​

Answer 1

Answer:

1.As 81 is the square of 9 and middle term 18 is double of this number, (compare it with (x+a)^2=x^2+2ax+a^2)

Hence x2+18x+81 is a complete square.

x^2+18x+81

= x^2+2×9×x+92

= (x+9)^2

4.Find factors of 9 and 16 whose products add to 24

Note that both  9and16 are squares .

3×4=12, and12+12=24

9x2+24x+16=(3x+4)(3x+4)