Answer:
Explanation:
21.
Your friend is wrong here. When they multiply by 3 in the second line, they need to ensure that every term is multiplied by 3. Although they have multplied x/3 and 6 by 3, they did not multiply 4 by 3.
The correct answer would be:
⇒ x + 12 < 18
⇒ x < 6
22.
Here your friend is wrong again. When they exapnd the bracket on the left hand side, they do not multiply all terms inside the bracket by 3. Although they have multplied w by 3, -2 has not been multiplied.
The correct answer would be:
⇒ 3w - 6 ≥ 10
⇒ 3w ≥ 16
⇒ w ≥ 16/3