Answer:
20. 8% increase = 108% total
2,550 × 1.08 = 2,754
D. 2,754 square feet
21. 25% off + 10% off = 65% total
239.99 × 0.65 = 155.9935
A. $156
22. Adding a negative number is the same as just subtracting.
D. 14 + (-9)
23. C. There is a change in temperature from -3°F to 3°F
24. C = pi × d
C = pi × 8
C = 25.1327
B. 25.1 units
25. 20 ÷ 4 = 5 pages per hour
25 ÷ 5 = 5 pph
D. Yes, because 20/4 = 25/5
26. A = Pi × r^2
9 ÷ 2 = 4.5
4.5^2 = 20.25
C. 20.25pi square inches
27. 100 ÷ 5 = 20
A. m = 20n
30. 250 + 20 - 270 = 0
A. Deposit $20 in the first week and withdraw $270 in the second week
31. 7.44 ÷ 24 = 0.31
A. C = 0.31b
32. -3(-6b + 5)
-3(-6b) + -3(5)
18b + (-15)
D. 18b - 15
33. -13.74 × 4 = -54.96
A. -54.96 feet
Answer:
the answer is C
Step-by-step explanation:
Step One
Add the first and third
-2x + 2y + 3z = 0
<u>2x + 3y + 3z = 5</u>
5y + 6z = 5
Step Two
Add the second and third together.
- 2x - y + z = -3
<u>2x + 3y + 3z = 5</u>
2y + 4z = 2 Divide this result by 2
y + 2z = 1 multiply this result by 5
5y + 10z = 5
Step three
Subtract the result of step 2 from the result of step one
5y + 10z = 5
<u>5y + 6z = 5 </u> Subtract
4z = 0
z = 0
Step Four
Solve for y
5y + 6z = 5 But z = 0
5y = 5
y = 1
Step Four
Solve for x . Use equation 3 in the givens.
2x + 3y + 3z = 5
2x + 3*1) + 3*0 = 5
2x = 5 - 3
2x = 2
x = 1
Answer
x = 1
y = 1
z =0 This has been checked and found to be correct.
Problem 2
Substitution is not the best way to do this. Divide the last equation by 2 and add it to the first one.
Step One
divide equation 3 by 2.
x + z = 2
Step Two
Add step one to equation 1
-x - y - z = - 8
<u>x + z = 2</u>
- y = - 6
y = 6
Step Three
Put this result into equation 1.
-x - 6 - z = - 8
-x - z = - 2
x + z = 2 Multiply this equation by 4
4x + 4z = 8
Step four
Put y = 7 into the second equation.
-4x + 4y + 5z = 7
-4x + 4*6 + 5z = 7
-4x + 24 + 5z = 7
-4x +5z = -17
Step 5
Add the results from Step 3 and Step 4 together.
-4x + 5z = - 17
4x + 4z = 8
9z = - 9
z = - 1
Step 6
Find x
-x - y - z = - 8
-x -6 + 1 =- 8
-x - 5 = - 8
-x = - 3
x = 3
Answers
x = 3
y = 6
z = -1 verified to be correct.
Answer:
no solution
Step-by-step explanation:
add 4k to both sides of the equation and you have ...
18 = -10 . . . . false
There is no value of k that will make this statement true. There is no solution.