<span>Let the cost of 2-scoop cones be x, and the cost of sundaes be y.
The first statement tells us that 5x = 3y
The second statement tells us that 9x + 6y = 19.95
Then we need to calculate the value of y (the cost of a sundae).
From our first equation, y = 5x/3. Substituting this into the second equation:
9x + 6(5x/3) = 19.95
9x + 10x = 19.95
19x = 19.95
x = 1.05
Substituting back into the first equation: 5(1.05) = 3y
5.25 = 3y
y = 1.75
Therefore the cost of a sundae is $1.75.
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The top row contains the product of

with each term of the expressions

and bottom row contains the product of -1 with each term of expression

.
The final result will be the sum of terms of both rows as shown below:
So the correct answer is option D
The only non-linear equation from your choices is the area of a circle as it is:
A=πr^2 and if you take the derivative of A you have:
dA/dr=2πr
So the rate of change changes as r changes, it is not constant thus the function has acceleration, so velocity changes.
This is in contrast to any linear equation which is of the form:
y=mx+b now taking the derivative you see that:
dy/dx=m, now m is a constant value, which means that there is no acceleration and the velocity remains constant.