2.
If one root of the equation 2x2 – 3x + c = 0 is 1, then other root is
(a) -1, (b) 2, c) { (d) none of these.
Answers
Answer :
1/2
Note:
★ The possible values of the variable which satisfy the equation are called its roots or solutions .
★ A quadratic equation can have atmost two roots .
★ The general form of a quadratic equation is given as ; ax² + bx + c = 0
★ If α and ß are the roots of the quadratic equation ax² + bx + c = 0 , then ;
• Sum of roots , (α + ß) = -b/a
• Product of roots , (αß) = c/a
Solution :
Here ,
The given quadratic equation is ;
2x² - 3x + c = 0
Now ,
Comparing the given quadratic equation with the general quadratic equation ax² + bx + c = 0 , we get ;
a = 2
b = -3
c = c
Also ,
It is given that one of the root of the given quadratic equation is 1 .
Thus ,
Let α = 1 and ß be the roots of the given quadratic equation .
Also ,
We know that , sum of the roots of the given quadratic equation will be given as ;
=> α + ß = -b/a
=> 1 + ß = -(-3)/2
=> 1 + ß = 3/2
=> ß = 3/2 - 1
=> ß = (3-2)/2
=> ß = 1/2
Hence ,
The other root of the given quadratic equation is ½ .
Required answer -
Question -
★ If one root of the equation 2x² – 3x + c = 0 is 1, then other root is (Options are given below) –
- a) -1
- b) 2
- c) ½
- d) None of these
Given that -
★ One root of the quadratic equation 2x² - 3x + c = 0
To find -
★ Other root (atq)
Solution -
★ Other root is ½
Using concept -
★ How the sum of roots of quadratic equation is given.
Using dimension -
★ α + ß = -b/a
Full solution -
~ As it's given that one root of the quadratic equation 2x² - 3x + c = 0. So now there is a need to compare them like the following,
ax² + bx + c = 0
(We use this equation here because it is the general form of quadratic equation).
Here,
- a = 2
- b = -3
- c = c
~ In this question it is also given that the root of a quadratic equation is 1 and we have to find the other root. Henceforth,
~ Let α and ß as the roots of the given equation.
Here,
☑️ α is 1
☑️ ß is ? [to find]
Henceforth,
➝ α + ß = -b/a
➝ 1 + ß = -(-3)/2
- - cancel -
➝ 1 + ß = 3/2
- (+ = -) ; (- = +)
➝ ß = 3/2 - 1
- LCM
➝ ß = (3-2) / 2
➝ ß = ½
Henceforth, ½ is the other root of the given quadratic equation..!