Alright.
For 7, you'll want to put congruent sides equal to each other, assuming they are parallelograms. So, you'll get the two equations:
3x+2=23
2y-7=9
Solve using GEMDAS/PEMDAS, and you'll get these answers.
3x+2=23
3x=21
x=7
2y-7=9
2y=2
y=1
For 8, you'll want to do the exact same thing, formatting the numbers to equal each other. You'll get these two equations:
3y+5=14
2x-5=17
Solving them would make:
3y+5=14
3y=9
y=3
2x-5=17
2x=22
x=11
For 9, you have to remember that the angle opposite of one angle in a defined parallelogram are congruent. Thus:
130=2h
5k=50
solve them and you get
h=65
k=10
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Hope that helped. Good luck.
Multiply 2x-5y= -21 by 3 to make it 6x-15y= -63
Multiply 3x-3y= -18 by -5 to make it -15x+15y=90
This cancels the y’s out which leaves us with
6x=-63
&
-15x=90
x for 6x=-63 equals - 10.5 so x is - 10.5 and for -15x=90, x= -6
Then you plug in x into any equation you’d like to find y.
Let’s plug in - 10.5 into 6x... equation.
6(- 10.5)-15y=-63
63-15y= -63
-63 -63
-15y=0
y=0 and x= - 10.5. When you plug in this values it makes the equation true!
But the correct answer is the first one north. Sorry if I’m doing too much hahah
If I’m confusing here’s the right answer...
6x-15y= -63
-15x+15y=90
Answer:
<em>Grades to be scored in 3rd exam = 88</em>
Step-by-step explanation:
Given that average of 3 numbers is 85.
First two numbers are 81 and 86.
To find:
3rd number so that average is 85
Solution:
Let the third number = 
Formula for average is:

Here, sum of numbers = 
Total count of numbers = 3

<em>Grades to be scored in 3rd exam = 88</em>
1/4 (8 + 6z + 12)
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Combine like terms :
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1/4 (6z + 20)
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Apply distributive property :
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1/4(6z) + 1/4(20)
3/2z + 5
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Answer: 3/2z + 5
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