Answer:
144
Step-by-step explanation:
12x12=144
y= 1.25x+6.75
Make 31.75 y because that is the total cost he paid.
1.25x+6.75=31.75
1.25x=25
x=20
So he had 20 refills.
Answer:
(a)

(b)

(c)

(d)

Step-by-step explanation:
(a)

we can use property of exponent

we get


........Answer
(b)

we can use property of exponent

we get


........Answer
(c)

we can use property of exponent

we get



........Answer
(d)

we can use property of exponent

we get


we can use property

........Answer
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