what is the answer for 4y^2=81

Answer:
either y = 4.5
or y = -4.5

Explanation:
To get the solution, we will need to isolate the y on one side of the equation.
This can be done as follows:
4y² = 81

[tex] \frac{4y^2}{4} = \frac{81}{4} [/tex]

y² = 20.25

y = +/- √(20.25)
either y = +√(20.25) = 4.5
or y = -√(20.25) = -4.5

Since there are no restrictions on the value of y, therefore, both answers would be accepted

Hope this helps :)