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 = 
= 
= 
The answer to the proportion is t=52.5
What must be true is the expression will actually be adding 10 + (+ x), because of the two marks you have to make when subtracting by a negative.
The subtraction sign is also the negative sign. So in this case, the expression is also saying -x, which means there is two negative signs.
A double negative is a positive, so in this case the x will be turned to a positive integer.
If this is still too confusing, she can plug in a number to replace x. Let’s try it with -2:
Ex. 10 - (-2)= 12.
The two negative signs turn into one positive sign, AKA an addition sign. So, the above expression can be simplified as 10 + 2, or 12.
The sale taxes s 0.70. So it would be $9.45.
Answer: 5/8 or 0.625
Step-by-step explanation:
3/2x1/4= 3/8
Then, 3/8x5/3= 15/24
15/24 simplified equals 5/8. 5/8 in decimal form is 0.625