Question

5. Which of the following represents the set B = {x:x is an interger, x^2+ 1 = 10)?

(A) B = {3}
(B) B-{-3,3}
(C)B- { }
(D) B-{-3, ..., 3}​

Answer 1

Answer:

B

Step-by-step explanation:

put the values of option into the question, Or solve the quadratic eq

x^2=10-1

x^2=9

x=√9

x=+-3

Answer 2

Answer:

(B) B = {-3,3}

Step-by-step explanation:

To find Set B we have to solve the equation

${x}^{2} + 1 = 10$

Now,

${x}^{2} + 1 = 10 \\ {x}^{2} + 1 - 10 = 0 \\ {x}^{2} - 9 = 0 \\ {x}^{2} - {3}^{2} = 0$

This is in the form of

${a}^{2} - {b}^{2} = (a + b)(a - b)$

So,

${x}^{2} - {3}^{2} = 0 \\ (x + 3)(x - 3) = 0 \: \: \: \\ so \: \: either \: \: x - 3 = 0 \: \: or \: \: x + 3 =0 \\ x = 3 \: \: \: or \: \: x = - 3$

So, Set B = {-3,3}