Q. 124.5( 4 Votes )
Solve for x and y:
2x + 3y + 1 = 0, 
Answer :
After rearrangement, we have
2x + 3y = - 1 …eq.1
…eq.2
Let us first simplify eq.2 by taking LCM of denominator,
Eq.1 ⇒ 
⇒ 7 – 4x = 3y
⇒ 4x + 3y = 7 …eq.3
To solve these equations, we need to make one of the variables (in both the equations) have same coefficient.
And it is so that the equations 1 & 3 have variable y having same coefficient already, so we need not multiply or divide it with any number.
Recalling equations 1 & 3,
2x + 3y = - 1
4x + 3y = 7
On solving these two equations we get,
⇒ x = 4
Substitute x = 4 in eq.1/eq.3, as per convenience of solving.
Thus, substituting in eq.3, we get
4(4) + 3y = 7
⇒ 16 + 3y = 7
⇒ 3y = 7 – 16
⇒ 3y = - 9
⇒ y = - 3
Hence, we have x = 4 and y = - 3
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