What is the sum of 667 and 23? a. 29 b. 15,341 c. 644 d. 690
1 answer:
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Answer:
-10
Step-by-step explanation:
You are asked to tell the y-value of the solution. You can find the whole solution and then report the y-value, or you can just find the y part of the solution. We choose the latter.
This is basically done by eliminating the x-variable. It can be done using the "elimination" method of solving these equations. And it can also be done using the "substitution" method of solving these equations. We choose the latter.
Add 14 to the second equation to solve for x:
... x = y + 14
Substitute this into the first equation.
... 3(y +14) -y = 22
... 2y +42 = 22 . . . . . . simplify
... y +21 = 11 . . . . . . . . divide by 2
... y = -10 . . . . . . . . . . subtract 21
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<em>Comment on additional solution methods</em>
A graphing calculator can show you the solution, as in the attachment. Of the solution (x, y) = (4, -10), we are only interested in y = -10.
Cramer's rule can find just one variable value, too. For that, it is convenient to write the system as ...
- 3x -y = 22
- x - y = 14 . . . . . add 14-y to the equation given
Then the solution for y is ...
... y = (22·1 -14·3)/(-1·1 -(-1)·3) = -20/2 = -10
Answer:
Joe's Plumbing charges more per hour ($45) than Mark's Plumbing (S40)
Step-by-step explanation:
Let
t ------> the number of hours
J(t) ---->the total amount in dollars that Joe's Plumbing charges
M(t) ---->the total amount in dollars that Mark's Plumbing charges
we know that
The linear equation in slope form is equal to
where
m is the slope or rate of the linear equation
b is the y-intercept (initial value)
In this problem we have
<em>Joe's Plumbing</em>
The slope or rate is equal to
Mark<em>'s Plumbing</em>
The slope or rate is equal to
therefore
Joe's Plumbing charges more per hour ($45) than Mark's Plumbing (S40)