Multiplication in simple equations

Multiplication in simple equations

The opposite of multiplication is division. Therefore, in solving equations which involve multiplication, you can also apply division.

Example 1

Find the value of x if $7 \times x = 49$.

Solution

The equation $7 \times x = 49$ can be written as $7x = 49$.

Make $x$ remain alone in the left hand side by dividing both sides of the equation by 7.

$\frac{7x}{7} = \frac{49}{7}$

$x = 7$

Therefore, the value of $x = 7$.

Example 2

Find the value of $n$ if $-3 \times n - 5 = 61$.

Solution

The equation $-3 \times n - 5 = 61$ can be written as $-3n - 5 = 61$.

Add 5 to both sides of the equation.

$-3n - 5 + 5 = 61 + 5$

$-3n + 0 = 66$

$-3n = 66$

Divide by $-3$ on both sides of the equation.

$\frac{-3n}{-3} = \frac{66}{-3}$

$n = -22$

Therefore, the value of $n = -22$.