If a + b = 41, and a − b = 38, find the value of (a + b)².

If  $$a^2+b^2 = 90$$​ and ab = 27, then find the possible value of $$\frac{a+b}{a-b}.$$​​

​$$\text{If }x + \frac{ 1}{x} = 17 \text{ then }x^2 + \frac{ 1}{x^2} \text{ is:}$$

If a + b = 41, and a − b = 38, find the value of (a + b)².

If 5x + 4y = 12 and xy = 2, then find the value of 125x³ + 64y³.