SSC CGL Algebra Practice Test 7
15 fresh SSC CGL algebra questions on identities, equations, polynomials, and substitution.
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SSC CGL Algebra Practice Test 7
15 fresh SSC CGL algebra questions on identities, equations, polynomials, and substitution.
Preview all 15 questions in SSC CGL Algebra Practice Test 7 (no login required)
- Identity
1. If x+y=5 and xy=6, then x²+y² is:
- A. 11
- B. 12
- C. 13 (Correct)
- D. 14
Explanation: x²+y²=(x+y)²−2xy=25−12=13.
- Linear Equation
2. Solve: 3x+7=25.
- A. x=5
- B. x=6 (Correct)
- C. x=7
- D. x=8
Explanation: 3x=18 → x=6.
- Quadratic
3. Roots of x²−5x+6=0 are:
- A. 2 and 3 (Correct)
- B. 1 and 6
- C. 3 and 4
- D. 2 and 4
Explanation: Factors: (x−2)(x−3)=0.
- Identity
4. If a−b=3 and a+b=7, then a²−b²=
- A. 18
- B. 21 (Correct)
- C. 24
- D. 28
Explanation: a²−b²=(a+b)(a−b)=7×3=21.
- Substitution
5. If x=2 and y=−1, value of x³−y³:
- A. 7
- B. 9 (Correct)
- C. 10
- D. 12
Explanation: x³−y³=8−(−1)=9.
- Linear Equation
6. If 2x+3y=12 and x−y=1, find x.
- A. 2
- B. 3 (Correct)
- C. 4
- D. 5
Explanation: From second: x=y+1. Substituting: 2(y+1)+3y=12 → 5y=10 → y=2, x=3.
- Polynomial
7. If x+1/x=3, find x²+1/x².
- A. 5
- B. 6
- C. 7 (Correct)
- D. 9
Explanation: (x+1/x)²=x²+2+1/x². So x²+1/x²=9−2=7.
- Identity
8. Value of (a+b)³−(a−b)³ in simplified form:
- A. 2b³
- B. 2a³
- C. 6a²b+2b³ (Correct)
- D. 6ab²+2b³
Explanation: Expand both cubes: (a+b)^3 - (a-b)^3 = a^3+3a^2b+3ab^2+b^3 - (a^3-3a^2b+3ab^2-b^3) = 6a^2b + 2b^3.
- Linear Equation
9. If 5x−3=2x+9, find x.
- A. 3
- B. 4 (Correct)
- C. 5
- D. 6
Explanation: 3x=12 → x=4.
- Substitution
10. If x=√5+√3 and y=√5−√3, find xy.
- A. 2 (Correct)
- B. 4
- C. 6
- D. 8
Explanation: xy=(√5+√3)(√5−√3)=5−3=2.
- Polynomial
11. If x=3, value of x³−9x+1:
- A. −1
- B. 0
- C. 1 (Correct)
- D. 2
Explanation: 27−27+1=1.
- Quadratic
12. For equation 2x²−7x+3=0, sum of roots is:
- A. 3/2
- B. 5/2
- C. 7/2 (Correct)
- D. 9/2
Explanation: Sum = 7/2 (from −b/a = 7/2).
- Identity
13. If x²+y²=17 and xy=4, find x+y.
- A. 4
- B. 5 (Correct)
- C. 6
- D. 7
Explanation: (x+y)²=x²+y²+2xy=17+8=25. x+y=5.
- Linear Equation
14. In a fraction, numerator is 3 less than denominator. If both are increased by 2, fraction becomes 4/5. Original fraction is:
- A. 7/10
- B. 8/11
- C. 9/12
- D. 10/13 (Correct)
Explanation: Let denominator be d, so numerator is d - 3. Then (d - 1)/(d + 2) = 4/5. Solving gives d = 13, so the original fraction is 10/13.
- Polynomial
15. Factor of x²−16 is:
- A. (x−4)(x+4) (Correct)
- B. (x−8)(x+2)
- C. (x−2)(x+8)
- D. (x+4)²
Explanation: Difference of squares: a²−b²=(a−b)(a+b).