If (2x-5)(2x+5) = 5 What is the value of 4x^2

A math problem I need help with from my SAT prep book. Thanks!

(2x-5)(2x+5) = 5
(2x-5)(2x+5) - 5 = 0
4x^2 - 25 - 5 = 0
4x^2 - 30 = 0{Take This}

4x^2 - 30 = 0
4x^2 = 30

The way to do it is expand out the brackets combine like terms refactorise and solve for x. I don't have time to do it myself so I plugged it into wolfram alpha.

x = + or - sqrt(15/2)

now just substitute this into 4x^2

4(15/2) = 2(15) = 30

hope this helps.

Note that, by expanding (2x - 5)(2x + 5), we see that:
(2x - 5)(2x + 5) = 4x^2 + 10x - 10x - 25 = 4x^2 - 25.

Thus, 4x^2 - 25 = 5. Adding 25 to both sides yields:
4x^2 = 5 + 25 = 30.

I hope this helps!

Its 30.
Just multiply (2x-5)(2x+5) and expand.

(2x - 5)(2x + 5) = 5

4x^2 - 25 = 5

4x^2 = 30

Expression on the left represents 'difference of two squares'
i.e. 4x^2 - 5^2

thus, 4x^2 = 5 + 25 = 30

The answer is 30

(2x-5)(2x+5)=5
4x^2-25=5
4x^2=30