Whakaoti i te (3+9i)(-9+7i)=

$$( 3 + 9 i ) ( - 9 + 7 i ) =$$

Aromātai

$$-90-60i$$

Ngā Upane Otinga

Me whakarea ngā tau matatini 3+9i me -9+7i pēnā i te whakarea huarua.

$$3\left(-9\right)+3\times \left(7i\right)+9i\left(-9\right)+9\times 7i^{2}$$

Hei tōna tikanga, ko te i^{2} ko -1.

$$3\left(-9\right)+3\times \left(7i\right)+9i\left(-9\right)+9\times 7\left(-1\right)$$

Mahia ngā whakarea.

$$-27+21i-81i-63$$

Whakakotahitia ngā wāhi tūturu me ngā wāhi pōhewa.

$$-27-63+\left(21-81\right)i$$

Mahia ngā tāpiri.

$$-90-60i$$

Wāhi Tūturu

$$-90$$

Ngā Upane Otinga

Me whakarea ngā tau matatini 3+9i me -9+7i pēnā i te whakarea huarua.

$$Re(3\left(-9\right)+3\times \left(7i\right)+9i\left(-9\right)+9\times 7i^{2})$$

Hei tōna tikanga, ko te i^{2} ko -1.

$$Re(3\left(-9\right)+3\times \left(7i\right)+9i\left(-9\right)+9\times 7\left(-1\right))$$

Mahia ngā whakarea i roto o 3\left(-9\right)+3\times \left(7i\right)+9i\left(-9\right)+9\times 7\left(-1\right).

$$Re(-27+21i-81i-63)$$

Whakakotahitia ngā wāhi tūturu me ngā wāhi pōhewa ki -27+21i-81i-63.

$$Re(-27-63+\left(21-81\right)i)$$

Mahia ngā tāpiri i roto o -27-63+\left(21-81\right)i.

$$Re(-90-60i)$$

Ko te wāhi tūturu o -90-60i ko -90.

$$-90$$