Q: Here are three questions in one that involve solving for variables:
(a) -2x = 5x + 18
(b) 4e + 3 = 7e + 9
(c) c – 1 = -11 + 3c
A: OK. Whenever you are solving for a variable, you want to get all the x’s on one side, and all the plain numbers on the other side:
(a) -2x = 5x + 18
Subtract 5x from both sides (that will get rid of the x’s on the right side of the equation and put them on the left side:
-2x – 5x = 5x + 18 – 5x
Simplify:
-7x = 18
Now, divide both sides by -7 to really get the x by itself!
-7x/-7 = 18/-7
x = 18/-7
And, there you go!
(b) 4e + 3 = 7e + 9
I will subtract 4e from both sides (putting all of the e’s on the right side):
4e + 3 – 4e = 7e + 9 -4e
Simplify
3 = 3e + 9
Now, subtract 9 from both sides:
3 – 9 = 3e + 9 – 9
-6 = 3e
Divide both sides by 3:
-6/3 = 3e/3
-2 = e
TADA! See that each one of my steps always makes progress in getting the variable by itself?
(c) c – 1 = -11 + 3c
Subtract c from both sides:
c – 1 – c = -11 + 3c – c
-1 = -11 + 2c
Add 11 to both sides:
-1 + 11 = -11 + 2c + 11
10 = 2c
Divide both sides by 2:
10/2 = 2c/2
5 = c
Okk thanks soo much im still having a little trouble with this stuff!! But im getting better thanks to you!!<33
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