Q3 of 23 Page 1

Attempt any three of the following sub questions:

Solve the following quadratic equation by completing square method:


x2 + 10x + 24 = 0.

x2 + 10x + 24 = 0

⇒ x2 + 2 × 5x + (25 - 1) = 0


⇒(x2 + 2 × 5x + 25) - 1 = 0


⇒ (x2 + 2 × 5x + 52) - 1 = 0 {Using (a + b)2 = a2 + b2 + 2ab }


⇒ (x + 5) 2 - 1 = 0


⇒ (x + 5) 2 = 1


Taking square root of both the sides,


⇒ (x + 5) = ±1


⇒ x + 5 = 1 and x + 5 = - 1


⇒ x = 1 – 5 and x = - 1 - 5


⇒ x = - 4 and x = - 6


More from this chapter

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3

Attempt any three of the following sub questions:

Solve the following simultaneous equations using graphical method.
x + y = 6;
x – y = 2.

 3

Attempt any three of the following sub questions:

There is an auditorium with 3s rows of seats. There are 20 seats in the first row, 22 seats in the second row, 24 seats in the third row and so on. Find the number of seats in the twenty - fifth row.

 4

Attempt any two of the following sub questions:

Two digit numbers are formed using the digits 0, 1, 2, 3, 4, 5 where digits are not repeated.
P is the event that the number so formed is even.
Q is the event that the number so formed is greater than 50.
R is the event that the number so formed is divisible by 3.
Then write the sample space S and events P, Q, R using set notation.

 4

Attempt any two of the following sub questions:

The following table shows ages of 300 patients getting medical treatment in a hospital on a particular day:



Find the median age of the patients.