Answer:
c. -4a + 22b
Step-by-step explanation:
Reasonable because the three items altogether cost about $40
12. Answer: 2130
<u>Step-by-step explanation:</u>
T = -0.01y + 10.6
9.2 = -0.01y + 10.6
<u>-10.6</u> <u> -10.6 </u>
-1.4 = -0.01y
<u> ÷-0.01</u> <u>÷-0.01 </u>
140 = y
"y" represents the number of years after 1990
1990 + 140
= 2130
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13. Answer: -0.0036° per foot
<u>Step-by-step explanation:</u>
Since the relationship is linear, then we can set up the values as x, y coordinates and use the slope formula to find the rate of degrees over feet.
(6562, 63) and (16405, 28)
rate = 
= 
= 
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14. Answer: $0.28 per kWh
<u>Step-by-step explanation:</u>
Same reason as #13
(200, 55) and (500, 140)
rate = 
= 
= 
Answer: There are 1436 bricks that he will need to make a brick wall.
Step-by-step explanation:
Since we have given that
Dimensions of a brick wall is given by
Length = 14.5 feet
Width = 0.5 feet
Height = 5.5 feet
Dimensions of a brick is given by
Length = 6 inch
Width = 4 inch
Height = 2 inch
We need to find the number of bricks :
So, Number of bricks is given by

Hence, there are 1436 bricks that he will need to make a brick wall.