Expansions Exercise 3.2



Please Select

Q1 If x - y = 8 and xy = 5, find x2 + y2



Q2 If x + y = 10 and xy = 21, find 2 (x2 + y2 ).



Q3 If 2a + 3b = 7 and ab = 2, find 4a2 + 9b2



Q4 If 3x - 4y = 16 and xy = 4, find the value of 9x2 + 16y2.



Q5 If x + y = 8 and x - y = 2, find the value of 2x2 + 2y2 .



Q6 If a2 + b2 = 13 and ab = 6, find
(i) a + b
(ii) a - b



Q8 If p - q = 9 and pq = 36, evaluate
(i) p + q
(ii) p2 - q 2 .



Q9 If x + y = 6 and x - y = 4, find
(i) x2 + y2
(ii) xy



Q10 If x - 3 = 1/x, find the value of x2 + 1/x2 .



Q11 If x + y = 8 and xy = 3 ¾, find the values of (i) x - y
(ii) 3 (x2 + y2 )
(iii) 5 (x2 + y2 ) + 4 (x - y).



Q12 If x2 + y2 = 34 and xy = 10 ½, find the value of 2 (x + y)2 + (x - y)2



Q13 If a - b = 3 and ab = 4, find a3 - b 3 .



Q14 If 2a - 3b = 3 and ab = 2, find the value of 8a3 - 27b3 .



Q15 If x + 1/x = 4, find the values of
(i) x2 + 1/x2
(ii) x4 + 1/x4
(iii) x3 + 1/x3
(iv) x - 1/x.



Q16 If x - 1/x = 5, find the value of 44 + 1/x4 .



Q17 If x - 1/x = √5, find the values of
(i) x2 + 1/x2
(ii) x + 1/x
(iii) x3 + 1/x3



Q18 If x + 1/x = 6, find
(i) x - 1/x
(ii) x2 - 1/x2



Q19 . If x + 1/x = 2, prove that x2 + 1/x2 = x3 + 1/x3 = x4 + 1/x4 .



Q20 If x - 2/x = 3, find the value of x3 - 8/x3



Q21 If a + 2b = 5, prove that a3 + 8b3 + 30ab = 125.



Q22 If a + 1/a = p, prove that a3 + 1/a3 = p (p2 - 3).



Q23 If x2 + 1/x2 = 27, find the value of x - 1/x.



Q24 If x2 + 1/x2 = 27, find the value of 3x3 + 5x - 3/x3 - 5/x.



Q25 If x2 + 1/25x2 = 8 3/5, find x + 1/5x



Q26 If x2 + 1/4x2 = 8, find x3 + 1/8x3 .



Q27 If a2
- 3a + 1 = 0, find (i) a2 + 1/a2
(ii) a3 + 1/a3 .



Q28 If a = 1/ (a - 5), find
(i) a - 1/a
(ii) a + 1/a
(iii) a2
- 1/a2 .



Q29 If (x + 1/x)2 = 3, find x3 + 1/x3 .



Q30 If x = 5 - 2√6, find the value of √x + 1/√x.



Q31 If a + b + c = 12 and ab + bc + ca = 22, find a2 + b2 + c2 .



Q32 If a + b + c = 12 and a2 + b2 + c2 = 100, find ab + bc + ca.



Q33 If a2 + b2 + c2 = 125 and ab + bc + ca = 50, find a + b + c.



Q34 If a + b - c = 5 and a2 + b2 + c2 = 29, find the value of ab - bc - ca



Q35 If a - b = 7 and a2 + b2 = 85, then find the value of a3 - b 3



Q36 If the number x is 3 less than the number y and the sum of the squares of x and y is 29, find the product of x and y.



Q37 If the sum and the product of two numbers are 8 and 15 respectively, find the sum of their cubes.



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