C. 8
d. 16
. Find x such that:
. (7/4) 3 * (7/4).5 = (7/4)x-2
. (125/8) * (125/8)* = (5/2)18
Simplify:
Answers
Answer:
x² + (x + 1)2 = 85
⇒ x² + x² + 2x + 1 = 85
⇒ 2x² + 2x + 1 – 85 = 0
⇒ 2x² + 2x – 84 = 0
⇒ x² + x – 42 = 0
⇒ x² + 7x – 6x – 42 = 0
⇒ x (x + 7) – 6 (x + 7) = 0
⇒ (x + 7) (x – 6) = 0
Either x + 7 = 0, then x = -7 or x – 6 = 0, then x = 6
(i) If x = -7, then the first number = -7 and second number = -7 + 1 = -6
(ii) If x = 6, then the first number = 6 and second number = 6 + 1 = 7
Hence numbers are -7, -6 or 6, 7
Question 2.
Divide 29 into two parts so that the sum of the squares of the parts is 425.
Solution:
Total = 29
Let first part = x
Then second part = 29 – x
According to the condition
x² + (29 – x)2 = 425
⇒ x² + 841 + x² – 58x = 425
⇒ 2x² – 58x + 841 – 425 = 0
⇒ 2x² – 58x + 416 = 0
⇒ x² – 29x + 208 = 0 (Dividing by 2)
⇒ x² – 13x – 16x + 208 = 0
⇒ x(x – 13) – 16 (x – 13) = 0
⇒ (x – 13) (x – 16) = 0
Either x – 13 = 0, then x = 13 or x – 16 = 0, then x = 16
(i) If x = 13, then First part =13 and second part = 29 – 13 = 16
(ii) If x = 16, then First part =16 and second part = 29 – 16 = 13
Parts are 13, 16
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