to #1: Expand the brackets, collect all terms with the variable at the LHS of the equation:
-1/6(x-18)+1/3(x+3)=x+4 <==> -1/6x+3 + 1/3x + 1 = 4 <==>1/6x=0 <==> x = 0
to #2:
There are 2 different ways to do the question:
First transform the mixed numbers into fractions and then subtract
or
subtract integers and fractions separately:
to #3:
You are dealing with a right triangle. Use the Pythagorean theorem. The lengths of the sides are known to you:
a = l -16
b = l - 2
c = l
Therefore:
Solve for l:
I've got x = 10 or x = 26
You have to decide which solution could be right
and why!