What is answer to number 3 plz hurry im timed

Question

y² = x² + 9     ... (Equation 1)

x² + y² = 41   ... (Equation 2)

Substitute (x² + 9) for y² in equation 2

x² + y² = 41   ... (Equation 2)

∴ x² + x² + 9 = 41

2x² + 9 = 41

2x² = 41 - 9

2x² = 32

(2x²)/2 = 32/2

x² = 16

x = +4 OR -4

Substitute 16 for x² in equation 1

y² = x² + 9    ... (Equation 1)

∴ y² = 16 + 9

y² = 25

y = +5 OR -5

Note that these values can be mixed in four ways
(4, -5), (4, 5), (-4, 5), (-4, -5)

The correct answer is the first choice

Aand b are correctly balanced reactions. they have the same number of atoms in both sides of the reaction