Question

What is the justification for the step taken from line 2 to line 3?

5 lines of math. The first line has, 3 x plus 9 minus 7 x equals x plus 10 plus x. The second line has, negative 4 x plus 9 equals 2 x plus 10. An arrow pointing from the front of the second line to the front of the third line. The third line has, negative 6 x plus 9 equals 10. The fourth line has, negative 6 x equals 1. The last line has x equals negative StartFraction 1 Over 6 EndFraction.

Answer 1

Explanation:

`3x+9-7x=x+10+x\\-4x+9=2x+10\\-6x+9=10\\`

• In the line 2, only variables were operated with a reduction of similar terms in each side of the equation, giving as result -4x at one side, and 2x at the other side.
• In the line 3, terms with variables were joined together in one side of the equation, and then, they were operate it, given as result -6X.

Answer 2

the subtraction property of equality

Explanation:

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