Call the notebooks x, and the pencils y. 
<span>3x + 4y = $8.50 and 5x + 8y = $14.50 </span>
<span>Then just solve as simultaneous equations: </span>
<span>3x + 4y = $8.50 </span>
<span>5x + 8y = $14.50 </span>
<span>5(3x + 4y = 8.5) </span>
<span>3(5x + 8y = 14.5) </span>
<span>15x + 20y = 42.5 </span>
<span>15x + 24y = 43.5 </span>
<span>Think: DASS (Different Add, Similar Subtract). 15x appears in both equations so subtract one equation from the other. Eassier to subtract (15x + 20y = 42.5) from (15x + 24y = 43.5) </span>
<span>(15x + 24y = 43.5) - (15x + 20y = 42.5) = (4y = 1) which means y = 0.25. </span>
<span>Then substitue into equation : </span>
<span>15x + 20y = 42.5 </span>
<span>15x + 5 + 42.5 </span>
<span>15x = 42.5 - 5 = 37.5 </span>
<span>15x = 37.5 </span>
<span>x = 2.5 </span>
<span>15x + 24y = 43.5 </span>
<span>15(2.5) + 24(0.25) </span>
<span>37.5 + 6 = 43.5 </span>
<span>So x (notebooks) are 2.5 ($2.50) each and y (pencils) are 0.25 ($0.25) each.</span>
        
             
        
        
        
Answer:
a. Non proportional 
b. Proportional 
c. Non proportional 
Step-by-step explanation:
Here, we want to determine if each situation is proportional or not 
a) Non-proportional
This is because the amount y paid in a month will be;
y = 1400x + 150
Since the amount paid is not solely dependent on the number of months, then we do not have a proportional relationship 
b) proportional 
y = 3/4x
The value of y is dependent solely on that of x, so the relationship is proportional 
c) non proportional 
Since the value of y is not solely entirely dependent on x value, then the relationship is not proportional 
 
        
             
        
        
        
Ratio and propoertion
cost/amount is constant
1235/95=x/285
cross multiply or time both sides by (95 times 283)
351975=95x
divide oth sies by 95
3705=x
the cost is $3705
        
             
        
        
        
We need the coefficient of determination definition 
The coefficient of determination (R²) is a number between 0 and 1 that measures how well a statistical model predicts an outcome. You can interpret the R² as the proportion of variation in the dependent variable that is predicted by the statistical model
So if we have a coefficient of determination of 0.233 we multiply by 100 to get the percentage
Answer: 23.3%
 
        
             
        
        
        
Answer:
he doesnt know how many tho lol
Step-by-step explanation: