Answer:
Given the system of equation:
......[1]
......[2]
we can rewrite equation [2] as;
......[3]
Substitute equation [3] into [1] to eliminate x, and solve for y;

Using distributive property: 

Combine like terms;
16 - 8y = -4
Add 4 to both sides we have;
20 - 8y = 0
Add 8y to both sides we have;
20 = 8y
Divide 8 to both sides we have;

Substitute the y-value in [3] we have;

x = 8 - 5 = 3
Therefore, the expression should be substituted into the first equation is,
and also the value of x = 3 and y = 2.5
Answer: y=3/2x
Step-by-step explanation:
First, to find the equation, we can figure out that the cost depends on how many tickets are bought. We can use cost as our y and # of tickets as our x.
An equation in slope intercept form is as follows:
y=mx+b
To get our slope, we must figure out the relationship between the cost and the number of tickets, or the y and the x.
We can use the slope formula,
, to find the slope, m.
= 
Thus, the slope of the equation is 3/2, making our final equation be y=3/2x.
Answer:
cups of pineapple juice .
Step-by-step explanation:
Equation of direct proportion between x and y:

As per given,
Let x = quantity of pineapple juice and y = quantity of orange juice.
,
, 
Put these values in an equation we get

Hence, he needs
cups of pineapple juice .
Answer:
is not; 90; right; wrong; 11; wrong
Step-by-step explanation: