What is (4i-5)(4i+5) ?

The solution to (4i-5)(4i+5) is -41

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular >

simplify (4i-5)(4i+5)

simplify

(4 i - 5) (4 i + 5)

- 41

Solution steps

(4 i - 5) (4 i + 5)

Rewrite

4 i - 5

in standard complex form:

- 5 + 4 i

Rewrite

4 i + 5

in standard complex form:

5 + 4 i

= (- 5 + 4 i) (5 + 4 i)

Apply complex arithmetic rule:

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

= (- 5 \cdot 5 - 4 \cdot 4) + (- 5 \cdot 4 + 4 \cdot 5) i

Simplify

(- 5 \cdot 5 - 4 \cdot 4) + (- 5 \cdot 4 + 4 \cdot 5) i : - 41

= - 41

18 + x - 9

3888

x^{4} - 2 x^{3} - 3 x^{2}

40 \times 7

40 \times 8