pencil is .10
pen is .90
Explanation:
x = pencil y = pen
3x + y = 1.20
7x + 2y = 2.50
try make x or y cancelable
-2 times (3x + y = 1.20) = -6x - 2y = - 2.40
7x + 2y = 2.50
-6x - 2y = - 2.40
x = .10
plug .10 back into one of the equations
3(.10) + y = 1.20
.30 + y = 1.20
y = .90