Differentiate both sides of the equation.

By the Sum Rule, the derivative of with respect to is .

Evaluate .

Since is constant with respect to , the derivative of with respect to is .

Differentiate using the Power Rule which states that is where .

Multiply by .

Evaluate .

Since is constant with respect to , the derivative of with respect to is .

Rewrite as .

Reorder terms.

By the Sum Rule, the derivative of with respect to is .

Since is constant with respect to , the derivative of with respect to is .

Since is constant with respect to , the derivative of with respect to is .

Add and .

Reform the equation by setting the left side equal to the right side.

Subtract from both sides of the equation.

Divide each term by and simplify.

Divide each term in by .

Simplify .

Cancel the common factor of .

Cancel the common factor.

Rewrite the expression.

Cancel the common factor of .

Cancel the common factor.

Divide by .

Simplify .

Multiply the numerator and denominator of by the conjugate of to make the denominator real.

Multiply.

Combine.

Simplify the denominator.

Add parentheses.

Raise to the power of .

Raise to the power of .

Use the power rule to combine exponents.

Add and .

Rewrite as .

Multiply by .

Dividing two negative values results in a positive value.

Replace with .

Find dy/dx 6x+7iy=18-21i