Hey there!
4x^2 - 121 + 5 = 0
COMBINE your LIKE TERMS
(4x^2) (-121 + 5) = (0)
(-121 + 5) = -116
New equation: 4x^2 - 116 = 0
ADD 116 to BOTH SIDES
4x^2 - 116 + 116 = 0 + 116
Cancel out: -116 + 116 because that gives you 0
Keep: 0 + 116 because that helps you solve for x
0 + 116 = 116
New equation: 4x^2 = 116
DIVIDE 4 to both sides
4x^2/4 = 116/4
Cancel out: 4/4 because that gives you 1
Keep: 116/4 because that helps you solve for x
Equation: x^2 = ± 116/4
116/4 = 29
Answer: x = √29 OR x = √-29
Good luck on your assignment and enjoy your day!
~Amphitrite1040:)