First solve for x in the first equation. So you'll have to substitute,
5(3x-7)=20
15x-35=20
Then add 35 to both sides.
15x=55
Divide 55 by 15.
So x = 3.66...
Then plug in 3.7 for x in 6x-8
6(3.7)-8
Its approximately 14.2
Problem 7: Correct
Problem 8: Correct
Problem 9: Correct
The steps are below if you are curious
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Problem 7
S = 180*(n-2)
2340 = 180*(n-2)
2340/180 = n-2
13 = n-2
n-2 = 13
n = 13+2
n = 15
I'm using n in place of lowercase s, but the idea is the same. If anything, it is better to use n for the number of sides since S already stands for the sum of the interior angles. I'm not sure why your teacher decided to swap things like that.
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Problem 8
First find y
y+116 = 180
y+116-116 = 180-116
y = 64
which is then used to find x. The quadrilateral angles add up to 180*(n-2) = 180*(4-2) = 360 degrees
Add up the 4 angles, set the sum equal to 360, solve for x
x+y+125+72 = 360
x+64+125+72 = 360 ... substitution (plug in y = 64)
x+261 = 360
x+261-261 = 360-261
x = 99
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Problem 9
With any polygon, the sum of the exterior angles is always 360 degrees
The first two exterior angles add to 264. The missing exterior angle is x
x+264 = 360
x+264-264 = 360-264
x = 96
Answer:
56
Step-by-step explanation:
First, convert the 70% so that we can use it with the 80 cups. To do this, convert the percent to a decimal by moving the decimal 2 spaces to the left:
70% → 70.00 → 0.70 → 0.7
70% percent can be seen as 0.7. Multiply this by 80:

So, 70% of 80 is 56. Desmond sold 56 cups on the second Saturday.
:Done
The median is 32; list numbers least to greatest, which ever is in the middle is the median
1. Add 9
2. Add 1/3
3. Add 15