Question 20718
i think you mean logs are to base 2..taking that and using the formula,
log x to base y = log x/log y
so we get
log(2x+8)/log 2+log (2x^2+21x+61)/log 2=-3
multiplying through out with log 2
log(2x+8)+log(2x^2+21x+61)=-3log 2=log 2^(-3)==log(1/2^3)=log(1/8)
log(2x+8)(2x^2+21x+61)=log(1/8)
(2x+8)(2x^2+21x+61)=(1/8)
i hope now you can continue from here
to simplify and factorise to get the answers