Please help and explain so I understand!!

Answer:
x=5
Step-by-step explanation:
[tex]4x^2-11=89[/tex]
add 11 to both sides
[tex]4x^2=100[/tex]
Divide 4 on both sides
[tex]x^2=25[/tex]
Take the square root of both sides to eliminate the power of two from x
[tex]\sqrt{x^2} =\sqrt{25}[/tex]
Simplify
[tex]x=5[/tex]