Math 7 ( Period 4)

Solving Equations With Mental Math 2.3

An identity equation is where ANY number can be substituted for the variable.
The equation will be TRUE.

What will happen is that while you are balancing the equation, you will ultimately end up with the same exact expression on each side. The Distributive Property is a good example of an IDENTITY EQUATION

3(x + 4) = 3x + 12

Since DP ALWAYS works that means that ANY NUMBER will for x

A conditional equation is one that has a variable where only certain values will make the equation true.

3x = 12 is conditional because 3x = 12 if and only if x = 4

You can use mental math to guess and check to solve simple equations 5y = 35

Instead of solving you think “what number times 5 will give me 35?

y = 7

Now you plug in your GUESS and CHECK that you are right> 5(7) = 35

Yes  7 is the solution