121)

If a + b = 24 and a² + b² = 306, where a > b, then the value of 4a - 5b is:

SSC CHSL 2021

A)

12

B)

18

C)

20

D)

15

122)

What is the coefficient of y² in the expansion of (√2y² - 5√3)³?

SSC CHSL 2021

A)

-30√3

B)

225√2

C)

30√3

D)

-225√2

123)

If x - y = 4 and x³ - y³ = 316, then the value of x⁴ + y⁴ is:

SSC CHSL 2021

A)

2248

B)

2284

C)

2428

D)

2482

124)

Simplify the following expression.
(2a - b - 3c)(4a² + b² + 9c² + 2ab + 6ac - 3bc)

SSC CHSL 2021

A)

8a³ + b³ + 27c³

B)

8a³ - b³ - 27c³ + 18abc

C)

-8a³ + b³ + 27c³

D)

8a³ - b³ - 27c³ - 18abc

125)

If a + b - c = 0, then what is the value of \(\frac{(b-c)^2}{4bc}\frac{(c-a)^2}{4ca}\frac{(a+b)^2}{4ab}\)?

SSC CHSL 2021

A)

\(-\frac{1}{2}\)

B)

\(\frac{1}{64}\)

C)

\(\frac{3}{4}\)

D)

\(-\frac{3}{4}\)

126)

If x - y = 4 and xy = 3, then what is the value of x³ - y³?

SSC CHSL 2021

A)

64

B)

100

C)

28

D)

88

127)

If (2a + 3b) (2c - 3d) = (2a - 3b) (2c + 3d), then:

SSC CHSL 2021

A)

\(\frac{b}{a}=\frac{c}{a}\)

B)

\(\frac{a}{b}=\frac{c}{d}\)

C)

\(\frac{a}{d} = \frac{c}{b}\)

D)

\(\frac{a}{b} =\frac{d}{c}\)

128)

If \((x^2+{1\over49x^2})=15{5\over7}\), then what is the value of \( \left(x+\frac{1}{7x}\right)\)?

SSC CHSL 2021

A)

7

B)

± 7

C)

4

D)

± 4

129)

If a + b + c = 2 and ab + bc + ca = -1, then the value of a³ + b³ + c³ - 3 abc is:

SSC CHSL 2021

A)

10

B)

14

C)

2

D)

5

130)

If x⁴ - 12x² + 1 = 0, then what will be the value of \(x^4+\frac{1}{x^4} \)?

SSC CHSL 2021

A)

144

B)

10

C)

146

D)

142