Question

the sum of two numbers is 9 and their product is 20 find the
sum of their squares and their cubes

Answer 1

Here is your answer.
xy=20 eq1

x+y=9
x=9-y

substitute value of x in eq1
xy=20
$(9 - y)y = 20 \\ 9y - {y}^{2} = 20 \\ 20 - 9y + {y}^{2} = 0 \\ {y}^{2} - 9y + 20 = 0 \\ {y}^{2} - 5y - 4y + 20 = 0 \\ y(y - 5) - 4 \: \: (y - 5) = 0 \\ (y - 5)(y - 4) \\ = y = 5 \: \: or \: y = 4$

Hope it helps you.
Plzz mark me as brainliest...