Find a quadratic polynomial each with the given numbers as the sum and product of its zeroes respectively.
(i) 41,−1
(ii) 2,31
(iii) 0,5
(iv) 1,1
(v) −41,41
(vi) 4,1
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Solution
A quadratic polynomial can be formed using the sum and product of its zeroes.
Step 1 — Polynomial for 41,−1
We use the general form for a quadratic polynomial.
The general form is P(x)=x2−(sum)x+(product).
Let's substitute the given values.
P(x)=x2−(41)x+(−1)
=x2−41x−1
We can multiply by a constant to remove fractions.
Let's multiply by 4.
P(x)=4(x2−41x−1)
=4x2−x−4
4x2−x−4
Step 2 — Polynomial for 2,31
We use the general form for a quadratic polynomial.
The general form is P(x)=x2−(sum)x+(product).
Let's substitute the given values.
P(x)=x2−(2)x+(31)
=x2−2x+31
We can multiply by a constant to remove fractions.
Let's multiply by 3.
P(x)=3(x2−2x+31)
=3x2−32x+1
3x2−32x+1
Step 3 — Polynomial for 0,5
We use the general form for a quadratic polynomial.
The general form is P(x)=x2−(sum)x+(product).
Let's substitute the given values.
P(x)=x2−(0)x+(5)
=x2+5
This is our polynomial.
x2+5
Step 4 — Polynomial for 1,1
We use the general form for a quadratic polynomial.
The general form is P(x)=x2−(sum)x+(product).
Let's substitute the given values.
P(x)=x2−(1)x+(1)
=x2−x+1
This is our polynomial.
x2−x+1
Step 5 — Polynomial for −41,41
We use the general form for a quadratic polynomial.
The general form is P(x)=x2−(sum)x+(product).
Let's substitute the given values.
P(x)=x2−(−41)x+(41)
=x2+41x+41
We can multiply by a constant to remove fractions.
Let's multiply by 4.
P(x)=4(x2+41x+41)
=4x2+x+1
4x2+x+1
Step 6 — Polynomial for 4,1
We use the general form for a quadratic polynomial.
The general form is P(x)=x2−(sum)x+(product).
Let's substitute the given values.