If x= 7y+3 and z= 49y^2 then what is 'z' in term of x?
A) 4
B) 3
C) 2
D) 6
Answers
Answered by
6
Heya !!
X = 7Y + 3
7Y = ( X - 3 )
Y = ( X - 3 / 7 )
And,
Z = 49Y²
Z = 49 × ( X - 3/7)²
=> 49 × ( X - 3 )² / (7)²
=> 49 × ( X - 3 )² / 49
=> ( X - 3 )²
=> ( X )² + (3)² - 2 × X × 3
=> X² + 9 - 6X
=> X² - 6X + 9
=> X² - 3X - 3X + 9
=> X ( X - 3 ) - 3 ( X - 3 )
=> ( X - 3 ) ( X - 3 ) = 0
=> ( X - 3 ) = 0
=> X = 3
Hence,
Option ( C ) is the correct answer.
X = 7Y + 3
7Y = ( X - 3 )
Y = ( X - 3 / 7 )
And,
Z = 49Y²
Z = 49 × ( X - 3/7)²
=> 49 × ( X - 3 )² / (7)²
=> 49 × ( X - 3 )² / 49
=> ( X - 3 )²
=> ( X )² + (3)² - 2 × X × 3
=> X² + 9 - 6X
=> X² - 6X + 9
=> X² - 3X - 3X + 9
=> X ( X - 3 ) - 3 ( X - 3 )
=> ( X - 3 ) ( X - 3 ) = 0
=> ( X - 3 ) = 0
=> X = 3
Hence,
Option ( C ) is the correct answer.
sorry for wrong options
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