# Find all real number solutions for the equation.?

a.) 3x^3 = 48x

b.) x^4 - 10,000 = 0

i have my answers but not 100% their right

any help would be appreciated.

Relevance
• Anonymous
9 years ago

a) 3x^3 = 48x

divide thru by 3x to get

x^2 = 16

so x = 4 or -4

b) x^4 - 10,000 = 0

10,000 is a perfect fourth power so

x = 10 or -10

Jim

Source(s): BS Computer Science
• 9 years ago

3x^3 (also means3.x.x.x) = 48x

(3.x.x.x)/x = 48x/x (divided both sides by x)

3x^2(or 3x.x) = 48

(3x^2)/3 = 48/3 (3 divided by both sides)

x^2 = 16(Square 16 because of x^2)

x = 4

x^4 - 10000 = 0 (Add 10000 in both sides)

+10000 +10000

x^4 = 10000

x = 10

• David
Lv 7
9 years ago

3x^3 - 48x = 0

3x(x^2 - 16) = 0

3x(x + 4)(x - 4) = 0

3x = 0

x= 0

x + 4 = 0

x = -4

x - 4 = 0

x = 4

x = {-4, 0, 4}

x^4 - 10000 = 0

(x^2 + 100)(x^2 - 100) = 0

(x^2 + 100)(x + 10)(x - 10) = 0

x^2 + 100 = 0

x^2 = -100

x = ± √-100

x = ± 10i

x + 10 = 0

x = -10

x - 10 = 0

x = 10

real number solutions

x = {-10, 10}