1. ## equation

a+8=12

t+(-3)=8

2. Originally Posted by dianna
a+8=12
You have $a+8=12$.

If two things are equal if you take the same thing from both the two results
are still equal.

So here we take (subtract) $8$ form $a+8$ and also from $12$, and the two results will be equal:

$
(a+8)-8=12-8
$

which gives:

$a=4$.

t+(-3)=8
This is the same thing as: $t-3=8$

Here we do the same sort of thing, we add $3$ to $t-3$ and $8$ to get:

$(t-3)+3=8+3$

which gives:

$t=11$

RonL

3. Originally Posted by dianna
a+8=12

t+(-3)=8
Whatever you do to one side of the equation, you must do to the other:
$a + 8 = 12$

$a + 8 - 8 = 12 - 8$

$a = 4$

=================================

$t+(-3)=8$

$t - 3 = 8$

$t - 3 + 3 = 8 + 3$

$t = 11$

-Dan