Please help i need help

Step-by-step 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

answer: a rhombus has two lines of symmetry that run through one vertex to the one directly across it. unlike a square, planes through the center of each edge of a rhombus do not yield mirrored sides.

step-by-step explanation: