Answer:
38.7
Step-by-step explanation:
Since you need an isolated variable to use the substitution method, we need to re-arrange one of the equations. This will probably be easiest to do with the first one.
Add 5y to both sides of the first equation.
x=10+5y
Now, in the second equation, put in 10+5y in any spot that has an x.
2(10+5y)-10y=20
Distribute the 2 to both numbers in the parenthesis.
20+10y-10y=20
Combine like terms.
20=20
This means that the two equations are actually the same. You can see this if you multiply the whole first equation by 2
2(x-5y=10)
2x-10y=20, which is the same as the second equation. Therefore, the two equations are actually the same one.
Answer:
F(8)=120
Step-by-step explanation:
f(x)=15x
f(8)=15(8)
f(8)=120
Answer: B) increasing for x < -4/3 and x > 4/3
decreasing for -4/3 < x < 4/3
<u>Step-by-step explanation:</u>
Graph the equation and follow the curve from left to right. If you are going up, it is increasing. If you are going down, it is decreasing.
Refer to the image below. Red is increasing. Blue is decreasing.
The vertices are at: x = -4/3 and x = 4/3
