Question

Mr. Barkley's solutions are wrong!
Determine the error which was made. Please be specific!
In what step was the error?
What was done incorrectly?
What should have been done instead?
Solve the problem correctly.

1. The problem: 14 = 4x – 2 (x – 5)

Mr. Barkley's solution:
14 = 4x – 2 (x – 5)
14 = 4x – 2x – 10
14 = 2x – 10
24 = 2x
12 = x
Solution: x = 12

2. Problem 2: 7 – 3a < 34

Mr. Barkley's solution:
7 – 3a < 34
- 3a < 27
Solution: a <-9

3. Problem 3:
Thelma has $178 in gift cards at the local hardware store. She plans to use them to buy a new set of wrenches and some welding rods. The wrench set costs $80. The welding rods are $10 per packet. What is the most number of packets of welding rods she will be able to buy?

Mr. Barkley's solution:
Let w = number of packets of welding rods.
100 + 10w < 178
10w < 78
w < 7.8
7.8 rounds to 8.
Solution: Thelma can buy at most 8 packets of welding rods.

Thank You So Much For Your Help!

(this is a repost pls dont ban me jiskha)

Answer 1

This where Barkley went wrong:
14 = 4x – 2 (x – 5)
14 = 4x – 2x – 10
it should be
14 = 4x - 2x + 10
14 = 2x + 10
4 = 2x
2 = x

- 3a < 27
a > -9
Note that change of direction of the inequality when multiplying by a negative value. This is just a shorthand way of moving stuff from one side to the other
- 3a < 27
0 < 27 + 3a
-27 < 3a
-9 < a
dividing by 3 does not change the direction

Let w = number of packets of welding rods.
100 + 10w < 178
This should be
Let w = number of packets of welding rods.
80 + 10w < 178
Now you can finish it off

Answer 2

@Oobleck CAn u help me on mine?

Answer 3

THANK YOU [[So Much]] FOR YOUR HELP!