I'd suggest using "elimination by addition and subtraction" here, altho' there are other approaches (such as matrices, substitution, etc.).
Note that if you add the 3rd equation to the second, the x terms cancel out, and you are left with the system
- y + 3z = -2
y + z = -2
-----------------
4z = -4, so z = -1.
Next, multiply the 3rd equation by 2: You'll get -2x + 2y + 2z = -2.
Add this result to the first equation. The 2x terms will cancel, leaving you with the system
2y + 2z = -2
y + z = 4
This would be a good time to subst. -1 for z. We then get:
-2y - 2 = -2. Then y must be 0. y = 0.
Now subst. -1 for z and 0 for y in any of the original equations.
For example, x - (-1) + 3(0) = -2, so x + 1 = -2, or x = -3.
Then a tentative solution is (-3, -1, 0).
It's very important that you ensure that this satisfies all 3 of the originale quations.
Answer:
The student's final grade in math 123 is 59.8.
Step-by-step explanation:
Note: The data in this question are merged. They are therefore sorted before answering the question as follows:
A student's math 123 grades are shown below.
Category Weight Grade
Homework 15% 36
Quiz 15% 60
Project 20% 75
Exam 1 15% 71
Exam 2 15% 9
Exam 3 20% 92
Calculate the student's final grade in math 123. Write your answer as a percent rounded to the nearest tenth. Don't include the percent sign.
Explanation to the answer is now given as follows:
The final grade of the student in math 123 can be calculated by adding together the products Weight and Grade obtained of each category as follows:
Final grade = (15% * 36) + (15% * 60) + (20% * 75) + (15% * 71) + (15% * 9) + (20% * 92) = 59.8%
The answer is already rounded to nearest tenth as required by the question.
Since the question also states that the percent sign should not be include, the student's final grade in math 123 is therefore 59.8.
Answer:
4 cookies
Step-by-step explanation:
Let the number of cookies he sold be c and that of brownies be b.
Assuming that brownies and cookies are the only type of baked goods sold,
b +c= 10 -----(1)
Amount of money received= $20
b(cost of brownie) +c(cost of cookie)= $20
2.50b +1.25c= 20 -----(2)
From (1): b= 10 -c -----(3)
Substitute (3) into (2):
2.50(10 -c) +1.25c= 20
Expand:
2.50(10) +2.50(-c) +1.25c= 20
25 -2.50c +1.25c= 20
-1.25c +25= 20
Being constants to 1 side:
-1.25c= 20 -25
-1.25c= -5
c= -5 ÷(-1.25)
c= 4
Thus, Joe sold 4 cookies.
Assuming you meant the x2 as x squared, then:
(11x+4)(11x-4)
Directly proportional, both increase/decrease, Multiple k(constant you needed to solve for)..
Inversely --one increases as the other decreases, increase the denominator & fraction gets smaller.... So
Problem:
Dirextly to X (× by X)
Inversely to Y, (÷ by Y)
Z= k X/Y
Solve, working backwards: Z =5 becomes
5 = k (X) ÷ (Y). And
X=15 and Y =9 becomes
5= k(15)/(9). Undo ÷9, ×9 both sides
45= k(15). Now undo ×15 by ÷15 both sides
45/15 = 3. So k=3, (also called your constant of variation)....and your Equation/Proportion becomes...
Z = 3X/Y
Use the new #s.... X=23, Y=14
Z= 3×23÷14 = 69/14. If they want spirochete answer divide and round to corresponding # if decimals
