Question
Find the roots
x1=22−7,x2=22+7
Alternative Form
x1≈−0.322876,x2≈2.322876
Evaluate
4x2−8x−3
To find the roots of the expression,set the expression equal to 0
4x2−8x−3=0
Substitute a=4,b=−8 and c=−3 into the quadratic formula x=2a−b±b2−4ac
x=2×48±(−8)2−4×4(−3)
Simplify the expression
x=88±(−8)2−4×4(−3)
Simplify the expression
More Steps

Evaluate
(−8)2−4×4(−3)
Multiply
More Steps

Multiply the terms
4×4(−3)
Rewrite the expression
−4×4×3
Multiply the terms
−48
(−8)2−(−48)
Rewrite the expression
82−(−48)
If a negative sign or a subtraction symbol appears outside parentheses, remove the parentheses and change the sign of every term within the parentheses
82+48
Evaluate the power
64+48
Add the numbers
112
x=88±112
Simplify the radical expression
More Steps

Evaluate
112
Write the expression as a product where the root of one of the factors can be evaluated
16×7
Write the number in exponential form with the base of 4
42×7
The root of a product is equal to the product of the roots of each factor
42×7
Reduce the index of the radical and exponent with 2
47
x=88±47
Separate the equation into 2 possible cases
x=88+47x=88−47
Simplify the expression
More Steps

Evaluate
x=88+47
Divide the terms
More Steps

Evaluate
88+47
Rewrite the expression
84(2+7)
Cancel out the common factor 4
22+7
x=22+7
x=22+7x=88−47
Simplify the expression
More Steps

Evaluate
x=88−47
Divide the terms
More Steps

Evaluate
88−47
Rewrite the expression
84(2−7)
Cancel out the common factor 4
22−7
x=22−7
x=22+7x=22−7
Solution
x1=22−7,x2=22+7
Alternative Form
x1≈−0.322876,x2≈2.322876
Show Solution
