5x – 10 = 3x – 10 – (x – 2 )
First you must multiply the x – 2 by -1 before you begin your steps of solving. The – (x – 2 ) is the same as – 1(x – 2 ) . So 5x – 10 = ????
I want the x-terms on the left side of the “=” and the number terms on the right side. But first simplify the right side. You will make fewer mistakes. 5x – 10 = 3x – 10 – x +2. You do know why the 2 is positive?
Simplifies to 5x-10 = 2x – 8.
NOW begin solving. I will begin solving: Subtract 2x from both sides.
This is how we “move the x-term” to the left side of the equation.
3x – 10 = – 8 Now ADD 10 to both sides. This is how we move the “-10 term” to the right side of the equation.
Did you notice that the 10 is negative, and that it is on the left side of the equation?
3x – 10 + 10 =-8 + 10 This becomes: 3x =2
How do we finish with 1x instead
of 3x? Divide by 3 or
multiply by 1/3 .
Thus 3x =2 becomes 3x/3 = 2/3 , I divided by 3 (or multiplied by 1/3). So we know x= 2/3.
YES, divide by 3 or multiply by 1/3 are the same!!
Thanks