Question
Find the roots
x1=21−157,x2=21+157
Alternative Form
x1≈−5.764982,x2≈6.764982
Evaluate
x2−x−39
To find the roots of the expression,set the expression equal to 0
x2−x−39=0
Substitute a=1,b=−1 and c=−39 into the quadratic formula x=2a−b±b2−4ac
x=21±(−1)2−4(−39)
Simplify the expression
More Steps

Evaluate
(−1)2−4(−39)
Evaluate the power
1−4(−39)
Multiply the numbers
More Steps

Evaluate
4(−39)
Multiplying or dividing an odd number of negative terms equals a negative
−4×39
Multiply the numbers
−156
1−(−156)
If a negative sign or a subtraction symbol appears outside parentheses, remove the parentheses and change the sign of every term within the parentheses
1+156
Add the numbers
157
x=21±157
Separate the equation into 2 possible cases
x=21+157x=21−157
Solution
x1=21−157,x2=21+157
Alternative Form
x1≈−5.764982,x2≈6.764982
Show Solution
