The polynomial which is in the form of ax2 + bx + c is known as quadratic polynomial. Here b or c may be 0 some times.
There are two types,
To solve quadratic equation, we follow different ways.
ii) Using quadratic formula
iii) Completing the square
Solve the following quadratic equations.
Problem 1 :
x2 + 7x + 6 = 0
Solution:
x2 + 7x + 6 = 0
x2 + x + 6x + 6 = 0
x(x + 1) + 6(x + 1) = 0
(x + 1)(x + 6) = 0
x + 1 = 0 or x + 6 = 0
x = -1 or x = -6
So, the solutions are x = -1 or x = -6.
Problem 2 :
x2 - 8x + 12 = 0
Solution:
x2 - 8x + 12 = 0
x2 - 2x - 6x + 12 = 0
x(x - 2) - 6(x - 2) = 0
(x - 2)(x - 6) = 0
x - 2 = 0 or x - 6 = 0
x = 2 or x = 6
So, the solutions are x = 2 or x = 6.
Problem 3 :
x2 + 5x - 24 = 0
Solution:
x2 + 5x - 24 = 0
x2 + 8x - 3x - 24 = 0
x(x + 8) - 3(x + 8) = 0
(x + 8)(x - 3) = 0
x + 8 = 0 or x - 3 = 0
x = -8 or x = 3
So, the solutions are x = -8 or x = 3.
Problem 4 :
x2 - 3x + 1 = 0
Solution:
Comparing x2 - 3x + 1 = 0 and ax2 + bx + c = 0, we get
a = 1, b = -3 and c = 1
By using quadratic formula,
Problem 5 :
x2 + 3x - 3 = 0
Solution:
Comparing x2 + 3x - 3 = 0 and ax2 + bx + c = 0, we get
a = 1, b = 3 and c = -3
By using quadratic formula,
Problem 6 :
x2 + 4x + 2 = 0
Solution:
Comparing x2 + 4x + 2 = 0 and ax2 + bx + c = 0, we get
a = 1, b = 4 and c = 2
By using quadratic formula,
Problem 7 :
x2 + 8x = 0
Solution:
x2 + 8x = 0
x(x + 8) = 0
x = 0 or x + 8 = 0
x = 0 or x = -8
So, the solutions are x = 0 or x = -8.
Problem 8 :
x2 - 10x = 0
Solution:
x2 - 10x = 0
Since we have only two terms in the given polynomial, we can factor the common term to find factors.
x(x - 10) = 0
x = 0 or x - 10 = 0
x = 0 or x = 10
So, the solutions are x = 0 or x = 10.
Problem 9 :
5x2 - 10x = 0
Solution:
5x2 - 10x = 0
5x(x - 2) = 0
5x = 0 or x - 2 = 0
x = 0 or x = 2
So, the solutions are x = 0 or x = 2.
Problem 10 :
x2 - 81 = 0
Solution:
x2 - 81 = 0
Using square root property, we can solve it.
x2 = 81
Taking square root on both sides, we get
x = √81
x = ± 9
So, the solutions are {9, -9}.
Problem 11 :
x2 - 121 = 0
Solution:
x2 - 121 = 0
x2 = 121
Taking square root on both sides, we get
x = √121
x = ± 11
So, the solutions are {11, -11}.
Problem 12 :
25 = 10x - x2
Solution:
x2 - 10x + 25 = 0
Write equation in factored form.
(x - 5)2 = 0
x - 5 = 0
x = 5
So, the solution is x = 5.
Problem 13 :
36 = 13x - x2
Solution:
x2 - 13x + 36 = 0
x2 - 9x - 4x + 36 = 0
x(x - 9) - 4(x - 9) = 0
(x - 4) (x - 9) = 0
x - 4 = 0 or x - 9 = 0
x = 4 or x = 9
So, the solutions are x = 4 or x = 9.
May 21, 24 08:51 PM
May 21, 24 08:51 AM
May 20, 24 10:45 PM