exam Maths Puzzle Numerical Ability

Can you explain to me about finding the LCD on Solving Equations Involving Rational Expressions.
((((8/7+2x + x+3/2x+7)))
(((3/x-5=3/3x-2)))

Read Solution (Total 0)

exam Other Question

subtract 3b^2+10b+4 from 10b^2+6b-9
i came up with this answer
7b^2+16b-5
but i have to show my work and i always have a problem when i have to put it on paper help me please?

6(x-7)-2(3+4)+3(x)=34