Question

Answer 1

13) \(=\dfrac{9}{4}x^2+9xy+9y^2\)

14) \(=2x^2+8x\sqrt{y}+8y\)

15) \(=x^2+\dfrac{1}{36}y^2+9+\dfrac{1}{3}xy+6x+y\)

16) \(=\dfrac{1}{4}x^2-4xy+16y^2\)

17) \(=\dfrac{x^2}{4}-4y^4\)

18) \(=x^4-16\)

19) \(=x^2+2xy+y^2+x^2-2xy+y^2=2x^2+2y^2\)

20) \(=4x^2+12x+9-x^2-2x-1=3x^2+10x+8\)

Answer 2

\(13,=\dfrac{9}{4}x^2+9xy+9y^2\\ 14,=2x^2+8x\sqrt{y}+8y\\ 15,=x^2+\dfrac{1}{36}y^2+9+\dfrac{1}{3}xy+y+6x\\ 16,=\dfrac{1}{4}x^2-4xy+16y^2\\ 17,=\dfrac{x^2}{4}-4y^4\\ 18,=x^4-16\\ 19,=x^2+2xy+y^2+x^2-2xy+y^2=2x^2+2y^2\\ 20,=\left(2x+3-x-1\right)\left(2x+3+x+1\right)=\left(x+2\right)\left(3x+4\right)\)