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Solve x2 - 8x - 20 = 0
x = 4, x = -5
x = -4, x = 5
x = 2, x = -10
x = -2, x = 10
Solution:
Let us factorize the quadratic equation to find the value of x by splitting the middle term.
Step 1: Identify the values of a, b and c.
In the above equation, a is coefficient of x2 = 1, b is the coefficient of x = - 8 and c is the constant term = - 20.
Step 2: Multiply a and c and find the factors that add up to b.
1 × (- 20) = - 20
⇒ - 10 and 2 are the factors that add up to b.
Step 3: Split bx into two terms.
x2 - 10x + 2x - 20 = 0
Step 4: Take out the common factors by grouping.
x(x - 10) + 2 (x - 10) = 0
(x - 10) (x + 2) = 0
By putting the factors equal to zero we get two values of x
x - 10 = 0 and x + 2 = 0
x = 10 and x = - 2
Thus, the two values that satisfy the equation are 10 and - 2.
Solve x2 - 8x - 20 = 0
x = 4, x = -5, x = - 4, x = 5, x = 2, x = -10, x = -2, x = 10
Summary:
The value of x for the equation x2 - 8x - 20 = 0 is x = 10, - 2 which satisfies the equation.
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