KVS MATHEMATICS QUIZ 64 (ALGEBRA)

Question 1:

If $x=7+4 \sqrt{3}$, then the value of $\left(x+\frac{1}{x}\right)$ is :

$8 \sqrt{3}$

14

49

48

Question 2:

If $4 a^{2}+b^{2}=18$ and $a b=4$, then the value of $(2 a+b)^{2}$ is ?

30

32

40

34

Question 3:

If $7 x-1=48$, then the value of $2 x^3+3 x$ is:

707

770

777

385

Question 4:

If $a+b+c=0$, then the value of $a^{3}+b^{3}+c^{3}$ is:

abc

$2 a b$

$3 a b c$

0

Question 5:

If $a+b=10$ and $a b=5$, then what is the value of $a^{2}+b^{2}$ ?

80

90

100

110

Question 6:

If $x+y=15$ and $x y=45$, then what is the value of $x^{2}+y^{2}$?

170

135

225

240

Question 7:

If $a^{2}-b^{2}=55$ and $a+b=11$ then find the value of $\frac{a^{3}+b^{3}}{a-b}$ ?

$\frac{524}{5}$

$\frac{529}{5}$

$\frac{539}{5}$

$\frac{589}{4}$

Question 8:

If $2 \mathrm{a}-\mathrm{b}=4$ and $3\mathrm{~b}+2 \mathrm{c}=44$, then the value of $a+b+c$ is:

22

24

28

20

Question 9:

Which of following is correct?

$(3 x+4 y)(4 x-3 y)=12 x^{2}+251 x y+12 y^{2}$

$(3 x+4 y)(4 x-3 y)=12 x^{2}-251 x y+12 y^{2}$

$(3 x+4 y)(4 x-3 y)=12 x^{2}+7 x y-12 y^{2}$

Question 10:

If $x+\frac{1}{x}=7$, then $x^{3}+\frac{1}{x^{3}}$ is equal to:

343

161

340

322