Answer:
C
Step-by-step explanation:
A: y=1.6X
B: y=2.5x
D: y=2x
C doesn't have a proportional relationship between X and Y
There are 6 candles in each set and there are two sets of candle. All in all, there are 12 pieces of candle. To determine the price per candle, we just have to divide the total cost to the number of candles.
Price per candle = $36/12
Price per candle = $3
Yes it is rational because it could be expressed as a fraction. 0.4444444 as a fraction is 4/9
First we note symmetry in the expression's coefficients.
We also note that 7*3=21, and 7+3=10.
From the rational roots theorem, we are tempted to try with 3 and 7 as coefficients of the factors.
Try
(7b+3)(3b+7)=21b^2+(49+9)b+21
By switching the sign of 3b+7 to 3b-7, we get the signs right, to check:
(7b+3)(3b-7)=21b^2+(9-49)b-21=21b^2-40b-21 ....right!
So
(7b+3)(3b-7)=21b^2-40b-21