Answer:
x = -2
y = 5
Step-by-step explanation:
Given two equations
1. 7x + 10y = 36
2. y = 2x + 9
Substitute 2x + 9 for y in equation 1.
We have
7x + 10y = 36
7x + 10(2x + 9) = 36
Distribute 10 into (2x + 9)
We have
7x + 10 x 2x + 10 x 9 = 36
7x + 20x + 90 = 36
27x + 90 = 36
Subtract 90 from both sides to eliminate 90 on the left side
27x + 90 - 90 = 36 - 90
27x = -54
Divide both sides by 27 to isolate x
27x/27 = -54/27
x = -2
Now substitute -2 into either equation to get y
Using equation 2, we have
y = 2x + 9
= 2 x -2 + 9
= -4 + 9
= 5
x = -2
y = 5
Check
7(-2) + 10(5) = 36
You need to understand that you're solving for the average, which you already know: 90. Since you know the values of the first three exams, and you know what your final value needs to be, just set up the problem like you would any time you're averaging something.
Solving for the average is simple:
Add up all of the exam scores and divide that number by the number of exams you took.
(87 + 88 + 92) / 3 = your average if you didn't count that fourth exam.
Since you know you have that fourth exam, just substitute it into the total value as an unknown, X:
(87 + 88 + 92 + X) / 4 = 90
Now you need to solve for X, the unknown:
87
+
88
+
92
+
X
4
(4) = 90 (4)
Multiplying for four on each side cancels out the fraction.
So now you have:
87 + 88 + 92 + X = 360
This can be simplified as:
267 + X = 360
Negating the 267 on each side will isolate the X value, and give you your final answer:
X = 93
Now that you have an answer, ask yourself, "does it make sense?"
I say that it does, because there were two tests that were below average, and one that was just slightly above average. So, it makes sense that you'd want to have a higher-ish test score on the fourth exam.
Answer:
G 15.99h > 188.55 + 9.75h
Step-by-step explanation:
[~Answer~] (4.):
<em>Hello there! I'm Avery, and I'm here to help you! I mostly believe the answer </em><em>is 1 2/3
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++</em>
[~Answer Explanation~]:
First:
Convert any mixed numbers to fractions.
Reduce fractions where possible.
Then your initial equation becomes:
356÷72
Applying the fractions formula for division,
=35×26×7
=70/42
Simplifying 70/42, the answer is
=1 2/3
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
[~Last Messages~]:
Okay, I really hope my answer is correct.
I am truly sorry if it's wrong :(
Have a great morning, afternoon, or night. <333
[-!AveryIsSomeHowAlive!-]
Answer:
a
Step-by-step explanation:
