Question
Simplify the expression
x4−20x2
Evaluate
x4−5x2×4
Solution
x4−20x2
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Factor the expression
x2(x2−20)
Evaluate
x4−5x2×4
Multiply the terms
x4−20x2
Rewrite the expression
x2×x2−x2×20
Solution
x2(x2−20)
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Find the roots
x1=−25,x2=0,x3=25
Alternative Form
x1≈−4.472136,x2=0,x3≈4.472136
Evaluate
x4−5x2×4
To find the roots of the expression,set the expression equal to 0
x4−5x2×4=0
Multiply the terms
x4−20x2=0
Factor the expression
x2(x2−20)=0
Separate the equation into 2 possible cases
x2=0x2−20=0
The only way a power can be 0 is when the base equals 0
x=0x2−20=0
Solve the equation
More Steps

Evaluate
x2−20=0
Move the constant to the right-hand side and change its sign
x2=0+20
Removing 0 doesn't change the value,so remove it from the expression
x2=20
Take the root of both sides of the equation and remember to use both positive and negative roots
x=±20
Simplify the expression
More Steps

Evaluate
20
Write the expression as a product where the root of one of the factors can be evaluated
4×5
Write the number in exponential form with the base of 2
22×5
The root of a product is equal to the product of the roots of each factor
22×5
Reduce the index of the radical and exponent with 2
25
x=±25
Separate the equation into 2 possible cases
x=25x=−25
x=0x=25x=−25
Solution
x1=−25,x2=0,x3=25
Alternative Form
x1≈−4.472136,x2=0,x3≈4.472136
Show Solution
