Question Details

Solve both equations and form a new equation in variable ‘z’ (reduce to lowest possible factor) using roots of equation 1 and 2 as per instructions given below.

1. 211x+9x2=0
2. (y2)2=214

What will be new equation if roots of this are highest root of equation 1 and lowest root of equation 2.

Options

A

8z234z9=0

B

4z220z+9=0

C

8z220z+9=0

D

4z234z9=0

E

None of these

Show Answer

Correct Answer :

Option B

4z220z+9=0

Solution :

To find the new equation in the variable z, we first need to solve both of the given equations and determine their roots.

Step 1: Solve Equation 1
The first equation is:
2-11x+9x2=0
To solve this, we can multiply the entire equation by x2 (assuming x0) to clear the denominators:
2x2-11x+9=0
We can solve this quadratic equation by factoring. We look for two numbers that multiply to 2×9=18 and add up to -11. These numbers are -2 and -9.
Splitting the middle term:
2x2-2x-9x+9=0
2x(x-1)-9(x-1)=0
(2x-9)(x-1)=0
This gives the roots:
x=92=4.5 and x=1
Thus, the highest root of equation 1 is:
z1=92

Step 2: Solve Equation 2
The second equation is:
(y-2)2=214
First, convert the mixed fraction to an improper fraction:
214=2×4+14=94
So the equation becomes:
(y-2)2=94
Taking the square root on both sides:
y-2=±32
This gives two cases for y:
Case 1: y=2+32=72=3.5
Case 2: y=2-32=12=0.5
Thus, the lowest root of equation 2 is:
z2=12

Step 3: Form the new equation in variable 'z'
The roots of the new equation are z1=92 and z2=12.
Let us find the sum and the product of these roots:
Sum of roots S=z1+z2=92+12=102=5
Product of roots P=z1×z2=92×12=94
The standard form of a quadratic equation is:
z2-Sz+P=0
Substituting S and P:
z2-5z+94=0
Multiplying the entire equation by 4 to reduce it to integer coefficients:
4z2-20z+9=0

Therefore, the correct option is:
4z2-20z+9=0

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