Question

three questions which i had made . yes i know their answers off course , but let's see do you know answers or not.

Q1 → √x , √y and √(10x+y) are whole numbers . find the smallest values of x and y , if
√(10x+y) = √x + √y +2 = x+y-6

Q2 → by Pythagoras theorem , we know that x²+y²=z²
(a) → if x is even and x<y ,
then , prove that
z² - y² = 2(y + z)
(b) → if x is odd and x<y ,
then , prove that
z² - y² = y + z
answer in image if don't know

Answer 1

I knew the last two but i don't know how you figured the first one

Answer 2

Question 1 answer is x=4 y=9