book Maths Puzzle Numerical Ability

I can not figure out for the life of me how to do this. I have tried so many times, please, HELP.

Solve:
3log(5x)+4log(2x)=3
log(125x^3)+log(16x^4)=3

Have I done it right so far? For some reason it seems wrong.Please help me!!

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book Other Question

Instructions: find the valueof the dicriminantand determine the number of real solutions for each equation.

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