Find the product of each pair of complex conjugates.

(3 + 8i)(3 – 8i) =

Step-by-step explanation:

By Difference of Squares,

a² - b² = (a + b)(a - b).

=> (3 + 8i)(3 - 8i) = 3² - (8i)²

= 9 - 64i² = 9 - 64(-1) = 73.

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15