Solving Equations

An equation is a mathematical statement formed by placing an equal sign between two numerical or variable expressions, as in $3x+5=11$ .

A solution to an equation is a number that can be plugged in for the variable to make a true number statement.

Example 1:

Solve: $15-x=12$

What number should be subtracted from $15$ to get $12$ ?

We know that 3 should be subtracted from $15$ to get $12$ . So,

$15-3=12$

Therefore,

$x=3$

Hence, the solution of $15-x=12$ is $3$ .

Example 2:

Solve: $7y=77$

What number when multiplied by $7$ gives $77$ ?

$11$ when multiplied by $7$ gives $77$ . So,

$7\cdot 11=77$

Simplify. We get:

$77=77$

So, the solution is $11$ .

Example 3:

Solve: $84÷z=12$

$84$ when divided by what number gives $12$ ?

The number, $84$ when divided by $7$ gives $12$ . So,

$84÷7=12$ .

Therefore,

$z=7$ .

Example 4:

Solve: $13.4-m=9.0$

What number when subtracted from $13.4$ gives $9.0$ ?

The number, $4.4$ when subtracted from $13.4$ gives $9.0$ . So,

$13.4-4.4=9.0$ .

Therefore,

$m=4.4$ .