What are the zeroes of f (x) = x2 - 2x - 3?
x = -3, 1
x = -3, -1
x = 3, 1
x = 3, -1
Solution:
The zeroes of the polynomial make the values of the whole polynomial equal to zero.
Let us factorise the polynomial 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 = -2 and c is the constant term = -3.
Step 2:
Multiply a and c and find the factors that add up to b.
1 × ( - 3) = - 3
⇒ -3 and 1 are the factors that add up to b.
Step 3:
Split bx into two terms.
x2 - 3x + 1x - 3 = 0
Step 4:
Take out the common factors by grouping.
x (x - 3) + 1 (x - 3) = 0
(x - 3) (x + 1) = 0
By putting the factors equal to zero we get two values of x
x - 3 = 0 and x + 1 = 0
x = 3 and x = - 1
Thus, the two values that satisfy the equation are 3 and - 1.
What are the zeroes of f (x) = x2 - 2x - 3? x = - 3, 1 x = - 3, - 1 x = 3, 1 x = 3, - 1
Summary:
The zeroes of the equation f (x) = x2 - 2x - 3 are x = 3, - 1 which satisfies the equation.
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