# Thread: justification

1. ## justification

The steps to solving an equation are shown below. Provide a justification for steps 2, 3, and 4.

1. 8x – 5 = -2x - 15. 1. Given
2. 10x – 5 = -15. 2.
3. 10x = -10. 3.
4. x = -1. 4.

2. What have you thought about so far, in this exercise?

3. 2. 10x-5=-15 multiply of equality
3. 10x=-10 adding of equality
4. x=-1 divide of equality

4. The steps to solving an equation are shown below. Provide a justification for steps 2, 3, and 4.

1. 8x – 5 = -2x - 15. 1. Given
2. 10x – 5 = -15. 2.
2. 10x-5=-15 multiply of equality
Is that your final answer? (meaning: are you sure about that?)

5. Hello, annad95!

The steps to solving an equation are shown below.
Provide a justification for steps 2, 3, and 4.

$\begin{array}{ccccccc}1.& 8x - 5 \:=\: -2x - 15 && 1.& \text{Given } \\ 2. & 10x - 5 \:=\: -15 && 2. & --- \\ 3. & 10x \:=\: -10 && 3. & --- \\ 4. & x \:=\: -1 && 4. & --- \end{array}$

Here's my version . . .

$\begin{array}{ccccccccc}1.& 8x - 5 \:=\: -2x - 15 && 1.& \text{Given } \\ 2. & 10x - 5 \:=\: -15 && 2. & \text{add'n of equality} & \text{(Add }2x\text{ to both sides)} \\ 3. & 10x \:=\: -10 && 3. & \text{add'n of equality} & \text{(Add 5 to both sides)} \\ 4. & x \:=\: -1 && 4. & \text{div'n of equality} & \text{(Divide both sides by 10)} \end{array}$

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