a)( x+1)²-(x+2)(x-2)=3, x∈ Z
(x²+2x+1)-(x²-4)=3
x²+2x+1-x²+4=3
2x+5=3
2x=3-5
x=-1
b) [tex]\frac{ \sqrt{81}+ \sqrt{225} }{2 \sqrt{27} } *y=8 \\ \frac{9+15}{6 \sqrt{3} } *y=8 \\ = \frac{24y}{6 \sqrt{3} }=8 \\ = \frac{4y}{ \sqrt{3}} =8 \\ y=2 \sqrt{3} [/tex], x∈ R
