Question
Simplify the expression
2x3−21
Evaluate
2x2×x−21
Solution
More Steps

Evaluate
2x2×x
Multiply the terms with the same base by adding their exponents
2x2+1
Add the numbers
2x3
2x3−21
Show Solution

Find the roots
x=2384
Alternative Form
x≈2.18976
Evaluate
2x2×x−21
To find the roots of the expression,set the expression equal to 0
2x2×x−21=0
Multiply
More Steps

Multiply the terms
2x2×x
Multiply the terms with the same base by adding their exponents
2x2+1
Add the numbers
2x3
2x3−21=0
Move the constant to the right-hand side and change its sign
2x3=0+21
Removing 0 doesn't change the value,so remove it from the expression
2x3=21
Divide both sides
22x3=221
Divide the numbers
x3=221
Take the 3-th root on both sides of the equation
3x3=3221
Calculate
x=3221
Solution
More Steps

Evaluate
3221
To take a root of a fraction,take the root of the numerator and denominator separately
32321
Multiply by the Conjugate
32×322321×322
Simplify
32×322321×34
Multiply the numbers
More Steps

Evaluate
321×34
The product of roots with the same index is equal to the root of the product
321×4
Calculate the product
384
32×322384
Multiply the numbers
More Steps

Evaluate
32×322
The product of roots with the same index is equal to the root of the product
32×22
Calculate the product
323
Reduce the index of the radical and exponent with 3
2
2384
x=2384
Alternative Form
x≈2.18976
Show Solution
