Solve (4-7i)(8i)

$$( 4 - 7 i ) ( 8 i )$$

Evaluate

$$56+32i$$

Solution Steps

Multiply 4-7i times 8i.

$$4\times \left(8i\right)-7\times 8i^{2}$$

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

$$4\times \left(8i\right)-7\times 8\left(-1\right)$$

Do the multiplications. Reorder the terms.

$$56+32i$$

Real Part

$$56$$

Solution Steps

Multiply 4-7i times 8i.

$$Re(4\times \left(8i\right)-7\times 8i^{2})$$

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

$$Re(4\times \left(8i\right)-7\times 8\left(-1\right))$$

Do the multiplications in 4\times \left(8i\right)-7\times 8\left(-1\right). Reorder the terms.

$$Re(56+32i)$$

The real part of 56+32i is 56.

$$56$$