The sum of all three is 6x^2y + 2xy^2
Find a common denominator so, 3/6 plus 4/6 = 7/6
Let M = marker cost
Let P = pencil cost
3 markers and 2 pencils cost 1.80 ==> 3M + 2P = 1.80
4 markers and 6 pencils cost 2.90 ==> 4M + 6P = 2.90
Multiply the first equation by (-3) and add it to the second equation
-9M - 6P = -5.40
4M + 6P = 2.90
-5M = -2.50
M = 0.50
Plug this value for M into the 1st equation and solve for P
3*(0.50) + 2P = 1.80
1.50 + 2P = 1.80
2P = 0.30
P = 0.15
So a marker costs 50 cents and a pencil costs 15 cents
