If the zeroes of the polynomial $$x^2 - ax + b$$ are 3 and 4, then ‘a’ and ‘b’ are respectively equal to
Given: The zeroes of the polynomial $$x^2 - ax + b$$ are 3 and 4.
To find: The values of a and b.
Answer:
Let p(x) be $$x^2 - ax + b.$$
Let's find the value of the equation by substituting x with 3.
p(3) = $$ (3^2 - 3a + b)$$
p(3) = 9 - 3a + b
9 - 3a + b = 0
-3a + b = -9
b = -9 + 3a → (Equation 1)
Now, let us find the value when x = 4.
p(4) = $$ (4^2 - 4a + b)$$
p(4) = 16 - 4a + b-4a + b = -16
b = -16 + 4a
Substituting (Equation 1) in place of b,
-9 + 3a = -16 + 4a
-9 + 16 = 4a - 3a
7 = a
a = 7
Now, substituting the value of a in b = -9 + 3a.
b = -9 + 3×7
b = -9 + 21
b = 12
Therefore, a = 7 and b = 12.
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