Could someone please show me what I did worng in my math questions? any help will be greatly appreciated! I put my teachers response under the questions

Question

4. Solve:
5|2x + 1 | = 55
Divide both side by 5: |2x+1|=11
2x+1=11 and 2x+1= -1
+1 +1 +1 +1
2x = 12 2x = -10
X=5 x=-6

What my teacher said was wrong~~
2x+1=11 and 2x+1= -11 YES, for both of these!
+1 +1 Absolutely not, why?

5. Solve:
1/2|4x – 8| - 7 = 3
½|4x-8|=10
|4x-8|=20
4x-8=20 or -4x+8=20
X=7 or x=-3
What my teacher said was wrong~~ missing steps at the end....

6. Evaluate the given expressions when a = 3, b = -3, c = 4, and d = -1.
c|a-b| + d
= -3|3-(-3)|
=-1(-6)=-6
Answer is -6
What my teacher said was wrong~~ incorrect substitution at the end

Answer 1

For #4, you are subtracting 1 from each part and not adding it.

subtracting 1 gives you 2x = 10 and
2x = -12
You had the right idea, but the adding 1 is wrong, you really subtracted 1.

Teacher was probably looking for you to show the adding 8 and dividing by 4 and for the other one subtracting 8 and dividing by -4.

4|3-(-3| + -1
4(6) + -1
24 +-1 = 23 It looks like you substituted -3 for c instead of 4