Ella G. answered • 03/28/22
Math Tutor for students of all ages and learning styles for 20+ years.
SOLVING FOR A VARIABLE
When The term equality is used – it means that there is an equal sign in the equation. The only important thing to remember is to keep it equal the same math operation must be done to each side.
Another name for equal is the same. When using the properties think of doing the same to each side of the equation.
2 + 1 = 3
2 + 1 is the same as 3
If we add the same number to each side of the equation it is still true.
The same as —> 2+1+6 = 3+6
Because sex with attitude side, the equation stayed true. Before it was 3=3 And now it is 9=9
Now look at subtracting from each side.
4=3+1
Solving it:
4=4
If I subtract two from each side, it stays equal.
4-2 = 3 + 1-2
Solving it, we see that 2=2
Two was subtracted from both sides of the equation. The new equation solved is 2=2. The equation remained true.
These are the steps used to solve equations with a variable. The sole purpose right now is to get the variable alone – it is called isolating the variable. Think of variables as not playing nice with the members and they must separate with the =.
X is not nice! —>X - 2 = 17
+2 +2. <— The opposite of -2 is +2
We add 2 to both sides to get X alone.
This equation simplifies to
X=17+2
17+2=19
Now, X = 19
This is the reason learning the inverse property is important is because it is how to isolate the variable in equations.
Once equation is solved for the variable check the answer. Replace ( or substitute) the variable with the answer and check.
Example: X + 7 = 20
- 7 - 7
———————-
X = 13
To Check: Replace the variable X with 13. Always put the number you’re substituting in parentheses!
(13) + 7 = 20
20 = 20 therefore your answer is correct.
If the number is substituted is the equation without parentheses, it becomes confusing if you were adding or multiplying. Look at the following example.
2X - 3 = -7
+3 +3
——————-
2X = -4
—- ——
2 2
X = -2
Substituting the -2 back into the equation with parentheses:
2(-2) - 3 = -7
-4 - 3 = -7
-7 = -7
Without using the parentheses:
2 - 2 - 3 not = 7 it would be equal to -3
Ella G.
You are correct, anything with an = sign is a solution. Without the = sign it’s considered an expression. I was just letting the viewers know that X is equal to 19 and 19 is the solution. I don’t believe it says anywhere in my lesson plan that X=19 is the solution.03/29/22
Mark M.
X = 19 is an equation. It is not a solution. The solution is 19 and is designated by {19}/03/29/22