Question

What mistake did Brianna make? On Line 1, Brianna should have subtracted 3 instead of adding -3. On Line 1, Brianna violated the addition property of equality. On Line 3, Brianna should have divided by 0.1 instead of subtracting 0.1. On Line 3, Brianna violated the addition property of equality.

Answer 1

It's C

Explanation:

Answer 2

Question:

Brianna solved a two-step equation, but she made a mistake along the way.

`0.1x + 3 = 1.7`

Line 1 :
`(-3) + 0.1x + 3 = 1.7 + (-3)`

Line 2 :
`0.1x = -1.3`

Line 3 :
`(-0.1) + 0.1x = -1.3 + (-0.1)`

Line 4:
`x = -1.4`

Answer:

On Line 3, Brianna should have divided by 0.1 instead of subtracting 0.1.

Explanation:

Required

Where did she make a mistake?

To do this, we simply analyse her workings one step at a time

Equation:
`0.1x + 3 = 1.7`

Line 1 :
`(-3) + 0.1x + 3 = 1.7 + (-3)`

This is correct because she subtracted 0.3 from both sides

Line 2 :
`0.1x = -1.3`

This is also correct because she performed the arithmetic correctly

Line 3 :
`(-0.1) + 0.1x = -1.3 + (-0.1)`

This is incorrect.

Division by 0.1 is expected not subtraction