3/6= 1/2. We need x-7/7 to equal 1/2. One way to do this is time multiply the numerator and denominator, and once you get that number, multiply the denominator and numerator. This is hard to explain, so I'll include a drawing of what im doing as well.
3×7=21; We mutliplied the numerator and denominator. Now the denominator and numerator has to equal 21.
(x-7)×6=21
Let's divide both sides by 6.
x-7=3.5
Let's add 7 to both sides.
X=10.5
So, X=10.5.