Maths log.+quadratic

1)log(b5)8 / log(b5)16
= (log8 / log5) / (log16 / log5)
= log 8 / log 16
= log 2^3 / log 2^4
= 3log 2 / 4 log 2
= 3/4
2a) (3-(y/4) ) (3-(y/4) )=26
3 - y/4 = +/- √26
y/4 = 3 +/-√26
y = 12 +/-4√26
y = 4(3 +/-√26)
b)Let the roots of the required equation are x ,
then y = 2x
sub to (3-(y/4) ) (3-(y/4) )=26 ,
(3 - 2x/4)(3 - 2x/4) = 26
(3 - x/2)^2 = 26
x^2 /4 - 3x + 9 = 26
x^2 - 12x + 36 = 104
x^2 - 12x - 68 = 0