What is b/3+1/8=19 I need help

If you're solving for b, then you'll want to add the fractions first. this means you have to make a common denominator --> 8b/24 + 3/24 (24 is lcm) = 19
so (8b+3)/24 = 19... get the denominator out by multiplying 24 to both sides
so
8b+3=456
     -3    -3
8b=453
divide both sides by 8 to get b alone
b=56.625