Let first number is x
second number be y
one number is four less than a second number: x=y-4
Three times the first is 6 more than 6 times the second: 3x=6y+6
substitute x=y-4 in 3x=6y+6
3x =6y+6
3(y-4)=6y+6
3y-12=6y+6
3y-6y=6+12
-3y=18
y=-6
substitute y=-6 in x=y-4
x=-6-4=-10
so first number is -10
second number is -6
