Question
Simplify the expression
8−x2−4x
Evaluate
23×8−x2−4x−4
Multiply the numbers
More Steps

Evaluate
23×8
Reduce the numbers
3×4
Multiply the numbers
12
12−x2−4x−4
Solution
8−x2−4x
Show Solution

Find the roots
x1=−2−23,x2=−2+23
Alternative Form
x1≈−5.464102,x2≈1.464102
Evaluate
23×8−x2−4x−4
To find the roots of the expression,set the expression equal to 0
23×8−x2−4x−4=0
Multiply the numbers
More Steps

Evaluate
23×8
Reduce the numbers
3×4
Multiply the numbers
12
12−x2−4x−4=0
Subtract the numbers
8−x2−4x=0
Rewrite in standard form
−x2−4x+8=0
Multiply both sides
x2+4x−8=0
Substitute a=1,b=4 and c=−8 into the quadratic formula x=2a−b±b2−4ac
x=2−4±42−4(−8)
Simplify the expression
More Steps

Evaluate
42−4(−8)
Multiply the numbers
More Steps

Evaluate
4(−8)
Multiplying or dividing an odd number of negative terms equals a negative
−4×8
Multiply the numbers
−32
42−(−32)
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+32
Evaluate the power
16+32
Add the numbers
48
x=2−4±48
Simplify the radical expression
More Steps

Evaluate
48
Write the expression as a product where the root of one of the factors can be evaluated
16×3
Write the number in exponential form with the base of 4
42×3
The root of a product is equal to the product of the roots of each factor
42×3
Reduce the index of the radical and exponent with 2
43
x=2−4±43
Separate the equation into 2 possible cases
x=2−4+43x=2−4−43
Simplify the expression
More Steps

Evaluate
x=2−4+43
Divide the terms
More Steps

Evaluate
2−4+43
Rewrite the expression
22(−2+23)
Reduce the fraction
−2+23
x=−2+23
x=−2+23x=2−4−43
Simplify the expression
More Steps

Evaluate
x=2−4−43
Divide the terms
More Steps

Evaluate
2−4−43
Rewrite the expression
22(−2−23)
Reduce the fraction
−2−23
x=−2−23
x=−2+23x=−2−23
Solution
x1=−2−23,x2=−2+23
Alternative Form
x1≈−5.464102,x2≈1.464102
Show Solution
