you can subtract 1/4 from each side to get b by itself on the left side of the equation.
1/4+b=10
-1/4 -1/4
b=10-1/4
in order to simplify further we need to make 10 a fraction by putting it over 1
10 1
b= -------- - ---------
1 4
next we need to find a common denominator. In this case that will be 4
the 1/4 does not change but we need to multiply both the top and bottom of the 10/1 by 4 since 4 times 1 is 4, our common denominator
we get
10*4 1
b= -------- - ---------
1*4 4
40 1
b= -------- - ---------
4 4
now just subtract the numerators or top numbers
b=39/4
you can also write this as a mixed number. Divide 39 evenly by 4 and put the remainder over 4
b=9 3/4