Solve first equation for y:
5x+y=10
y=10-5x. Plug this equation into second equation
-x-(10-5x)=-2
-x-10+5x=-2
4x=8
x=2 (plug x into first equation)
5(2)+y=10
y=0
Answer:

Step-by-step explanation:
Given:
The expression to expand is given as:

Let us expand the first two binomials of the given expression using FOIL method.
The FOIL method states that:


Now, let us multiply the result with the remaining binomial. Multiplying each term of the trinomial with each term of the binomial, we get:

Therefore, the equivalent expression after expanding is given as:

Answer:
The t-distribution is used.
Step-by-step explanation:
When we dont know the standard deviation of the population, we use the t-distribution(t-table).
Otherwise, the z-distribution(z-table) is used.
So the answer to this question is the t-distribution.