Mathematics
Find the values of x and y if :
(i) (x - 1, y + 3) = (4, 4)
(ii) (3x + 1, 2y - 7) = (9, - 9)
(iii) (5x - 3y, y - 3x) = (4, - 4)
Coordinate Geometry
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Answer
Since two ordered pairs are equal, their first components are equal and their second components are separately equal.
(i) (x - 1, y + 3) = (4, 4)
⇒ x - 1 = 4 and y + 3 = 4
⇒ x = 4 + 1 and y = 4 - 3
⇒ x = 5 and y = 1
Hence, x = 5 and y = 1.
(ii) (3x + 1, 2y - 7) = (9, - 9)
⇒ 3x + 1 = 9 and 2y - 7 = -9
⇒ 3x = 9 - 1 and 2y = -9 + 7
⇒ 3x = 8 and 2y = -2
⇒ x = and y = -
⇒ x = and y = -1
Hence, x = and y = -1.
(iii) (5x - 3y, y - 3x) = (4, - 4)
⇒ 5x - 3y = 4 …………….(1)
And, y - 3x = - 4
⇒ y = -4 + 3x …………….(2)
Putting the value of y in (1), we get
⇒ 5x - 3(-4 + 3x) = 4
⇒ 5x + 12 - 9x = 4
⇒ 5x - 9x = 4 - 12
⇒ - 4x = - 8
⇒ x =
⇒ x = 2
Putting the value of x in (2),
y = - 4 + 3x
⇒ y = - 4 + 3 x 2
⇒ y = - 4 + 6
⇒ y = 2
Hence, x = 2 and y = 2.
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