Question 42103
First you need to find the equation

{{{6*(x-15)}}} would be 6 times the sum of a number and -15.  "is" in a word problem like this always means equals
{{{6*(x-15)=76+4x}}} more than means to add just like sum.  So this is the equation now you simply solve for x

{{{6x-90=76+4x}}}  Multiply the six to get rid of paranthesis (sp)
{{{2x=166}}}  Add 90 to both sides, and subtract 4x from both sides to get like variables on the same side
{{{x=83}}}  Divide both sides by 2.