book Maths Puzzle Numerical Ability

This new math sure gets me. I am a senior and trying to answer this question.
[2x(9+7)-4]/7=
Thank you.

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book Other Question

(((x-10)/(.5(x-10)))100)/10%=.4
I know that the answer is 9.6 but I can not figure out how. Can someone tell me if I did this correctly

3(x-5) + 3x = 4x + 5

I get an answer of x = 10