Answer:
22.
log3(4) + log3(5x^2 + 1) = 2
<=> log3(4 x (5x^2 + 1)) = log3(9)
<=> 20x^2 + 4 = 9
<=> 20x^2 = 5
<=> x^2 = 1/4
<=> x = +/- (1/2)
23.
log8(4x^2 + 1) - log8(2) = log8(5)
<=> log8((4x^2 + 1)/2) = log8(5)
<=> 2x^2 + 1/2 = 5
<=> 2x^2 = 9/2
<=> x^2 = 9/4
<=> x = +- (3/2)
24.
log8(4x^2 - 9) - log8(5) = 1
<=> log8((4x^2 - 9)/5) = log8(8)
<=> (4x^2 - 9)/5 = 8
<=> 4x^2 - 9 = 40
<=> 4x^2 = 49
<=> x^2 = 49/4
<=> x = +/- (7/2)
Hope this helps!
:)