Multiplying/Dividing Equations

Multiplying/Dividing Equations

Here are a few things to remember...

To solve multiplication equations

• Must do the inverse operation... which is division

• Division property of Equality says we must divide both sides of the equation by the same number

• ***OUR GOAL IS TO GET THE VARIABLE ON A SIDE BY ITSELF WITH A +1 AS THE COFEEICIENT***

Multiple Choice

 $6d=24$  

•  $d=144$  

•  $d=4$  

• Neither

Multiple Choice

 $20=-4y$  

•  $y=5$  

•  $y=-5$  

•  $y=80$  

•  $y=-80$  

• none of these

To solve a division equation

• You must to the inverse operation.... which is multiplication

• Multiplication property of Equality says we must multiply both sides of the equation by the same number

• ***OUR GOAL IS TO HAVE THE VARIABLE ON A SIDE BY ITSELF WITH A COEFFICIENT OF +1***

Multiple Choice

 $\frac{x}{3}=-6$  

•  $x=-2$  

•  $x=2$  

•  $x=-18$  

•  $x=18$  

• none of these

Multiple Choice

 $\frac{c}{8}=-7$  

•  $c=56$  

•  $c=-56$  

•  $c=-\frac{7}{8}$  

•  $c=\frac{7}{8}$  

• none of these

When you have a fraction as a coefficient... how do you "undo" multiplying by a fraction?

 $\frac{2}{5}p=6$  

• You need to use the multiplicative inverse which will give you a 1 as the coefficient

•  $\frac{5}{2}\cdot\frac{2}{5}=\frac{10}{10}=1$  

• Multiply both sides by  $\frac{5}{2}$  

•  $\frac{5}{2}\cdot\frac{2}{5}p=6\cdot\frac{5}{2}$  

•  $p=\frac{30}{2}=15$  

Multiple Choice

What is the multiplicative inverse of

 $-\frac{8}{5}$  

•  $\frac{8}{5}$  

•  $\frac{5}{8}$  

•  $-\frac{5}{8}$  

Multiple Choice

 $-\frac{8}{5}b=8$  

•  $b=1$  

•  $b=-1$  

•  $b=5$  

•  $b=-5$  

• none of these

Multiple Choice

 $\frac{3}{8}h=-9$  

•  $h=-24$  

•  $h=24$  

•  $h=27$  

•  $h=-27$  

• none of these

Multiple Choice

 $-14=\frac{2}{3}x$  

•  $x=2\ \frac{1}{3}$  

•  $x=-2\ \frac{1}{3}$  

•  $x=-21$  

•  $x=21$  

• none of these