Apabila a : b=2 : 5 carilah; (a+b)² : (a-b)²=(c+d)² : (c-d²)

[tex](a + b) ^{2} \div (a - b) ^{2} \\ (2 + 5) ^{2} \div (2 - 5) ^{2} \\ ({7}^{2}) \div ( { - 3}^{2} ) \\ 49 \div 9 \\ 5.4[/tex]