Solve (-1+21)(2+2)/-i

$$\frac { ( - 1 + 21 ) ( 2 + 2 ) } { - i }$$

Evaluate

$$80i$$

Solution Steps

Add -1 and 21 to get 20.

$$\frac{20\left(2+2\right)}{-i}$$

Add 2 and 2 to get 4.

$$\frac{20\times 4}{-i}$$

Multiply 20 and 4 to get 80.

$$\frac{80}{-i}$$

Multiply both numerator and denominator by imaginary unit i.

$$\frac{80i}{-i^{2}}$$

By definition, i^{2} is -1. Calculate the denominator.

$$\frac{80i}{1}$$

Divide 80i by 1 to get 80i.

$$80i$$

Real Part

$$0$$

Solution Steps

Add -1 and 21 to get 20.

$$Re(\frac{20\left(2+2\right)}{-i})$$

Add 2 and 2 to get 4.

$$Re(\frac{20\times 4}{-i})$$

Multiply 20 and 4 to get 80.

$$Re(\frac{80}{-i})$$

Multiply both numerator and denominator of \frac{80}{-i} by imaginary unit i.

$$Re(\frac{80i}{-i^{2}})$$

By definition, i^{2} is -1. Calculate the denominator.

$$Re(\frac{80i}{1})$$

Divide 80i by 1 to get 80i.

$$Re(80i)$$

The real part of 80i is 0.

$$0$$