Respuesta :

Answer:

whats nine + 10

Step-by-step explanation:

21

pencil is .10

pen is .90

Step-by-step 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