@DearGozde Many individuals already have the correct answer. But the answer is 4.
First you subtract 3 from each side.
5Xsquared = 80
second: divide both sides by 5.
Xsquared = 16
There fore the square root of x=4.
@Freya_24mU Remember, a negative times a negative number equals a positive. Therefore, (-4 squared equals a positive. (16+44)/4=15. you could also say: 16/4+(44/4) =15.