Answer:39
Hope it helps :)
Point are set up (x,y) you sub the number for x into the equation and see if you get the number for y.
y=4x+3
y=4 (5)+3
y=20+3
y=23
so A isn't the answer
y=4 (17)+3
y=68+3
y=71
B isn't the answer
y=4 (4)+3
y=16+3
y=19
and because 4 is the x value for c and d and there can only be 1 y value for each x you're answer is C because when x=4 y =19 or (4,19)
Answer
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This would be 21.5π * 360 / 20 yd^2 = 1215.18 yd^2 ( using pi = 3.14)
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Answer: 
Step-by-step explanation:
Use the power rule for differentiation.
Let S = spoon
Let K = knife
1 knife is thee times the cost of a spoon, so it would be 3S
Now you have 9S + 12K = 82.80
We can replace the K with 3S:
9S +12(3S) = 82.80
Simplify the left side:
9S + 36S = 82.80
Add:
45S = 82.80
Divide both sides by 45"
S = 82.80 / 45
S = 1.84
One spoon cost $1.84
We know one knife cost 3 times as much, so multiply the cost of a spoon by 3:
Knife = 1.84 x 3 = $5.52
