Let's suppose that we want to solve an equation like
For this, we can use the multiplication principle. The multiplication principle tells us that multiplying (or dividing) both sides of an equation by the same number does not change its solution.
In this case, the variable is being divided by To isolate , we can perform the opposite operation, which is multiplying by . So, we multiply both sides of the equation by
Now, we can cancel a common factor of from both the numerator and denominator.
Thus, our solution is Let's check that this solution is correct by plugging it back into the original equation:
Find the value of that satisfies the equation
In the equation, is being divided by To isolate , we can perform the opposite operation, which is multiplying by . So, we multiply both sides of the equation by
Now, we can cancel a common factor of from both the numerator and denominator.
If $\dfrac m 8= 11$, then $m = $
a
|
$\dfrac {11} 8$ |
b
|
$-3$ |
c
|
$3$ |
d
|
$19$ |
e
|
$88$ |
If $\dfrac{z}{6}=-6,$ then $z=$
a
|
$z=-36$ |
b
|
$z=-1$ |
c
|
$z=1$ |
d
|
$z=\dfrac{1}{2}$ |
e
|
$z=-12$ |
If then
First, let's swap the left and right-hand sides so that the variable is on the left-hand side.
In this equation, is being divided by To isolate , we can perform the opposite operation, which is multiplying by So, we multiply both sides of the equation by and simplify.
If $\dfrac{1}{4}=\dfrac{g}{12},$ then $g=$
a
|
$6$ |
b
|
$3$ |
c
|
$-8$ |
d
|
$-3$ |
e
|
$8$ |
If $-\dfrac{1}{3}=\dfrac{m}{6},$ then $m=$
a
|
$-\dfrac{2}{3}$ |
b
|
$2$ |
c
|
$-\dfrac{1}{18}$ |
d
|
$-2$ |
e
|
$\dfrac{1}{18}$ |
In order to remove a negative sign from our variable, we can multiply both sides by . This way, the two negatives will cancel out to form a positive.
For example, suppose that we have the equation
We can isolate by multiplying both sides of the equation by as follows:
Therefore, the solution to the equation is Let's check to see that this works by substituting our solution back into the original equation.
Find the value of that satisfies the equation
First, let's remove the negative sign from the variable. To do this, we multiply both sides of the equation by
In the equation above, is being divided by To isolate , we can perform the opposite operation, which is multiplying by . So, we multiply both sides of the equation by and simplify.
If $-\dfrac{c}{5}=3,$ then $c=$
a
|
$-15$ |
b
|
$-\dfrac{5}{3}$ |
c
|
$15$ |
d
|
$-\dfrac{3}{5}$ |
e
|
$\dfrac{3}{5}$ |
If $-\dfrac{p}{3}=\dfrac{1}{6},$ then $p=$
a
|
$-2$ |
b
|
$\dfrac{1}{2}$ |
c
|
$-\dfrac{1}{2}$ |
d
|
$\dfrac{1}{18}$ |
e
|
$-\dfrac{1}{18}$ |
To solve an equation like , we again need to look at what's happening to the variable and ask ourselves what the opposite operation is.
In this case, the variable is being multiplied by To isolate , we can perform the opposite operation, which is dividing by . So, we divide both sides of the equation by
Now, we can cancel a common factor of from both the numerator and denominator.
Let's check that our answer is correct by plugging it back into the original equation:
Note: If there is a negative coefficient on a variable, we can get rid of it by dividing, like we do with positive coefficients. For example:
Solve the equation
First, let's write the equation in a way that's a little more familiar to us. We can do this by swapping the left and right-hand sides of the equation.
In this case, the variable is being multiplied by To isolate , we can perform the opposite operation, which is dividing by . So, we divide both sides of the equation by and simplify.
If $6y = 14$, then $y = $
a
|
$\dfrac 3 7$ |
b
|
$20$ |
c
|
$\dfrac 7 3$ |
d
|
$8$ |
e
|
$7$ |
If $-4x = -36$, then $x=$
a
|
$-9$ |
b
|
$-4$ |
c
|
$9$ |
d
|
$4$ |
e
|
$-40$ |