A scatter plot matrix shows all pairwise scatter plots for many variables. If the variables tend to increase and decrease together, the association is positive. If one variable tends to increase as the other decreases, the association is negative, I hope this helps
The general equation of a line is
y= ax + b
where a is the slope
So a = -7
So y= -7x + b
But it passes through the point (5, -3)
Substitute the coordinates to calculate b:
So -3 = -7(5) + b
-3 = -35 + b
b= 35-3
b= 32
So the equation of the line of slope -7 and passing through the point (5, -3) is
y= -7x + 32
To answer this question you should begin with the coin that has a higher value. If you start with the dime and then just add the correct number of pennies to total $0.40, you will see that you will need 3 dimes ($0.30) and 10 pennies ($0.10).
I used a guess and check strategy starting with 2 dimes.