Solve r=3a*3(5ab)=

$$r = 3 a \cdot 3 ( 5 a b ) =$$

Solve for b (complex solution)

$$\left\{\begin{matrix}b=\frac{r}{45a^{2}}\text{, }&a\neq 0\\b\in \mathrm{C}\text{, }&r=0\text{ and }a=0\end{matrix}\right.$$

Steps for Solving Linear Equation

Multiply a and a to get a^{2}.

$$r=3a^{2}\times 3\times 5b$$

Multiply 3 and 3 to get 9.

$$r=9a^{2}\times 5b$$

Multiply 9 and 5 to get 45.

$$r=45a^{2}b$$

Swap sides so that all variable terms are on the left hand side.

$$45a^{2}b=r$$

Divide both sides by 45a^{2}.

$$\frac{45a^{2}b}{45a^{2}}=\frac{r}{45a^{2}}$$

Dividing by 45a^{2} undoes the multiplication by 45a^{2}.

$$b=\frac{r}{45a^{2}}$$

Solve for b

$$\left\{\begin{matrix}b=\frac{r}{45a^{2}}\text{, }&a\neq 0\\b\in \mathrm{R}\text{, }&r=0\text{ and }a=0\end{matrix}\right.$$

Steps for Solving Linear Equation

Multiply a and a to get a^{2}.

$$r=3a^{2}\times 3\times 5b$$

Multiply 3 and 3 to get 9.

$$r=9a^{2}\times 5b$$

Multiply 9 and 5 to get 45.

$$r=45a^{2}b$$

Swap sides so that all variable terms are on the left hand side.

$$45a^{2}b=r$$

Divide both sides by 45a^{2}.

$$\frac{45a^{2}b}{45a^{2}}=\frac{r}{45a^{2}}$$

Dividing by 45a^{2} undoes the multiplication by 45a^{2}.

$$b=\frac{r}{45a^{2}}$$

Solve for a (complex solution)

$$\left\{\begin{matrix}a=-\frac{b^{-\frac{1}{2}}\sqrt{5r}}{15}\text{; }a=\frac{b^{-\frac{1}{2}}\sqrt{5r}}{15}\text{, }&b\neq 0\\a\in \mathrm{C}\text{, }&r=0\text{ and }b=0\end{matrix}\right.$$

Solve for a

$$\left\{\begin{matrix}a=\frac{\sqrt{\frac{5r}{b}}}{15}\text{; }a=-\frac{\sqrt{\frac{5r}{b}}}{15}\text{, }&\left(r\geq 0\text{ and }b>0\right)\text{ or }\left(r\leq 0\text{ and }b<0\right)\\a\in \mathrm{R}\text{, }&r=0\text{ and }b=0\end{matrix}\right.$$