Solve with substitution 3x + y =19 -6x - 5 = y​

What are “like terms”? why can we only add like terms?

Galen sold tickets of his church’s carnival for a total of $2,820. children’s tickets cost $3 each and adult tickets cost $5 each. the number of children’s tickets sold was 30 more than 3 times the number of adult tickets slod. how many children’s ticket and how many adult tickets did he sell?

Which equation represents h for right triangle abc