# Ella's question from Facebook (solving for a variable)

#### Jameson

Staff member
I have 3 problems I'm stuck on. Anyone please help. B=1/9(one ninth)pi to the 2nd power t and trying to solve for t

Then this one, c=1/2(half)mr solving for m

And solve the formula for the indicated variable P=a+2b+4c, for a.

#### Jameson

Staff member
1) I'm not sure exactly what you mean by this. Is this it?

$$\displaystyle B=\frac{1}{9} \pi ^2 t$$

2) $$\displaystyle c=\frac{1}{2}mr$$

Multiply both sides by 2.

$$\displaystyle 2c=1*m*r$$ or just $$\displaystyle 2c=mr$$

Divide both sides by r.

$$\displaystyle \frac{2c}{r}=m$$ so $$\displaystyle m=\frac{2c}{r}$$

3) $P=a+2b+4c$ and solve for $a$

Subtract $2b$ from both sides.

$P-2b=a+4c$.

Subtract $4c$ from both sides.

$P-2b-4c=a$ or $a=P-2b-4c$