y*y=5*5+(5*3)*(5*3)

Solution for y*y=5*5+(5*3)*(5*3) equation:

Simplifying
y * y = 5 * 5 + (5 * 3)(5 * 3)

Multiply y * y
y2 = 5 * 5 + (5 * 3)(5 * 3)

Multiply 5 * 5
y2 = 25 + (5 * 3)(5 * 3)

Multiply 5 * 3
y2 = 25 + (15)(5 * 3)

Multiply 5 * 3
y2 = 25 + 15(15)

Multiply 15 * 15
y2 = 25 + 225

Combine like terms: 25 + 225 = 250
y2 = 250

Solving
y2 = 250

Solving for variable 'y'.

Move all terms containing y to the left, all other terms to the right.

Simplifying
y2 = 250

Take the square root of each side:
y = {-15.811388301, 15.811388301}