simplify (4+i)(9-i)

Solution

simplify

(4 + i) (9 - i)

37 + 5 i

Solution steps

(4 + i) (9 - i)

Apply complex arithmetic rule:

(a + bi) (c + d i) = (a c - b d) + (a d + b c) i

= (4 \cdot 9 - 1 \cdot (- 1)) + (4 (- 1) + 1 \cdot 9) i

Simplify

(4 \cdot 9 - 1 \cdot (- 1)) + (4 (- 1) + 1 \cdot 9) i : 37 + 5 i

= 37 + 5 i

x y^{5} z^{20}

\frac{11 !}{6 ! ( 11 - 6 ) !}

n^{2} - 289

12 + \frac{16}{3}

x^{4} - 9 x^{3} + 27 x^{2} - 27 x