Hello,
just add the two equations and make it equal to 180 and solve..
here, 15x + 4 + 10x + 1 = 180
now combine 15x and 10x to get 25x and 4and 1 to get 5
now we have 25x + 5 = 180
subtract 5 from 180 to get 175
then divide by 25 to get 7
X = 7
hope it helped.
