Question
Find the roots
Find the roots of the algebra expression
x1=2−26,x2=2+26
Alternative Form
x1≈−2.898979,x2≈6.898979
Evaluate
x2−4x−20
To find the roots of the expression,set the expression equal to 0
x2−4x−20=0
Substitute a=1,b=−4 and c=−20 into the quadratic formula x=2a−b±b2−4ac
x=24±(−4)2−4(−20)
Simplify the expression
More Steps
Evaluate
(−4)2−4(−20)
Multiply the numbers
More Steps
Evaluate
4(−20)
Multiplying or dividing an odd number of negative terms equals a negative
−4×20
Multiply the numbers
−80
(−4)2−(−80)
Rewrite the expression
42−(−80)
If a negative sign or a subtraction symbol appears outside parentheses, remove the parentheses and change the sign of every term within the parentheses
42+80
Evaluate the power
16+80
Add the numbers
96
x=24±96
Simplify the radical expression
More Steps
Evaluate
96
Write the expression as a product where the root of one of the factors can be evaluated
16×6
Write the number in exponential form with the base of 4
42×6
The root of a product is equal to the product of the roots of each factor
42×6
Reduce the index of the radical and exponent with 2
46
x=24±46
Separate the equation into 2 possible cases
x=24+46x=24−46
Simplify the expression
More Steps
Evaluate
x=24+46
Divide the terms
More Steps
Evaluate
24+46
Rewrite the expression
22(2+26)
Reduce the fraction
2+26
x=2+26
x=2+26x=24−46
Simplify the expression
More Steps
Evaluate
x=24−46
Divide the terms
More Steps
Evaluate
24−46
Rewrite the expression
22(2−26)
Reduce the fraction
2−26
x=2−26
x=2+26x=2−26
Solution
x1=2−26,x2=2+26
Alternative Form
x1≈−2.898979,x2≈6.898979
Show Solution