4(5x-20)= -20
20x-80= -20
+80 +80
____________
20x=60
_______
20
x=3
Answer:
1. 
2. 
Step-by-step explanation:
<u>Problem #1:</u>
1. Find the GCF (Greatest Common Factor)
2. Factor out the GCF and simplify.
3. Factor 
<u>Which two numbers add up to 7 and multiply to 10?</u>
2 and 5
<u>Rewrite the expression using the above.</u>
4. Done!
<u>Problem #2:</u>
1. Find the GCF (Greatest Common Factor)
2. Factor out the GCF and simplify.
3. Use the perfect square formula. 
4. Done!
I will give you everything I can do:
11)
Lets say Car A travels at x mph. That means Car B travels at x+2 mph.
Both of them are traveling towards each others, so we can say the total speed is 2x+2.
Now i takes 3 hrs and we know the distance.
Since R*T=D
Then 3(2x+2)=270
So 2x+2=90
2x=88
x=44
12)
To find perpendicular we want to find the opposite reciprocal of the original slope. Therefore the slope is 3/2.
Now we must find the equation of the line with the given variable.
First find b.
5=3/2*4+b
b = -1
So the equation of this line is:
y=3/2x-1
13) All work will be shown below.
6-3(-2-4x)=2(3(x-4)+7)
6+6+12x=2(3x-12+7)
12+12x=2(3x-5)
12+12x=6x-10
6x=-2
x = -1/3
14)
First we must find the amount each train traveled.
The speed of F train(Freight train)=x
The speed of P train(passenger train)=x+6
Their combined speed is 2x+6
It takes 2 hrs to cover 100 miles
So 2(2x+6)=100
2x+6=50
2x=44
x=22
So the freight train covered 44 miles and the passenger train covered 56 miles.
To find average speed you must do Total Distance/Total Time.
44/2 and 56/2
Which are 22 and 28.
The average speed of F train is 22 mph and average speed of P train is 28 mph.
15) Again opposite reciprocal.
3/5 -> -5/3
Work:
-4=-3*-5/3+b
-4=5+b
b=-9
y = -5/3x-9
16)
F=kx-kx0
First kx0 = 0
So F=kx
So x=F/k
Answer:
The answer is A
Step-by-step explanation:
Supplementary angles are angles which add up to 180°
∠1 and ∠3 add up to 180°, so they are supplementary.
