Sep 16, 2020

Finding quadratic equations of given roots.

 Find the quadratic equations of the following:

1. -2 and 3

2. 1/2 and 1

3. +√5 and -√5

Solutions:

1. -2 and 3 

Let x= -2 and x= 3

X+2=0 and x-3=0

Put the two equations into two different brackets and equate all to 0

(X+2)(X-3)=0

Expand brackets(remove brackets by multiplying every term in the first bracket by each term in the second bracket)

X(X-3)+2(X-3)=0

x² -3x + 2x -6=0

x² - x - 6=0


2. ½ and 1

Let x=½ and x=1

x-½=0 and x-1=0

To eliminate the fraction in the first equation, multiply by 2

2x-1=0 and x-1=0

(2x-1)(x-1)=0

Expand

2x(x-1)-1(x-1)=0

2x² -2x-x+1=0

2x²-3x+1=0


3. +√5 and -√5

Let x=+√5 and x=-√5

x-√5=0 and x+√5=0

(x-√5)(x+√5)=0

Expand

x(x+√5)-√5(x+√5)=0

x²+x√5-x√5-5=0

x²-5=0

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Finding quadratic equations of given roots.

 Find the quadratic equations of the following: 1. -2 and 3 2. 1/2 and 1 3. +√5 and -√5 Solutions: 1. -2 and 3  Let x= -2 and x= 3 X+2=0 and...