Question
Simplify the expression
x4−90x2
Evaluate
x4−10x2×9
Solution
x4−90x2
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Factor the expression
x2(x2−90)
Evaluate
x4−10x2×9
Multiply the terms
x4−90x2
Rewrite the expression
x2×x2−x2×90
Solution
x2(x2−90)
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Find the roots
x1=−310,x2=0,x3=310
Alternative Form
x1≈−9.486833,x2=0,x3≈9.486833
Evaluate
x4−10x2×9
To find the roots of the expression,set the expression equal to 0
x4−10x2×9=0
Multiply the terms
x4−90x2=0
Factor the expression
x2(x2−90)=0
Separate the equation into 2 possible cases
x2=0x2−90=0
The only way a power can be 0 is when the base equals 0
x=0x2−90=0
Solve the equation
More Steps

Evaluate
x2−90=0
Move the constant to the right-hand side and change its sign
x2=0+90
Removing 0 doesn't change the value,so remove it from the expression
x2=90
Take the root of both sides of the equation and remember to use both positive and negative roots
x=±90
Simplify the expression
More Steps

Evaluate
90
Write the expression as a product where the root of one of the factors can be evaluated
9×10
Write the number in exponential form with the base of 3
32×10
The root of a product is equal to the product of the roots of each factor
32×10
Reduce the index of the radical and exponent with 2
310
x=±310
Separate the equation into 2 possible cases
x=310x=−310
x=0x=310x=−310
Solution
x1=−310,x2=0,x3=310
Alternative Form
x1≈−9.486833,x2=0,x3≈9.486833
Show Solution
