Math 6 Honors Periods 6 & 7 (Tuesday)

Solving Equations 11-7

Now that we have learned about negative integers, we can solve an equation such as
x + 7 = 2

subtract 7 from both sides
x + 7 = 2
-7 = -7

ask yourself 'Who Wins? and set up a side bar with the winner on top.

Then take the difference. So in this case we know that -7 wins-- so our answer will end up being negative. We put 7 on top and take the difference 7 -2 = 5
x = -5

What happens if we have 3x = 15. First looking at the problem, notice that x is being multiplied by 3-- so we need to use the inverse to isolate the variable. So we will divide by 3

3x /3 = 15/3 or x = 15

But what happens if we have 1/2 x + 3 = 0. First we need to separate the variable from the addition or subtraction operation so we use the inverse of + 3 and subtract 3 from both sides
1/2 x + 3 - 3 = 0 - 3 or 1/2x = -3
Now, we need to multiply both sides by 2/1 ( the reciprocal of 1/2)
(2/1)1/2x = -3(2/1) or x = -6