Q. 34.0( 18 Votes )
Solve for x and y:
2x + 3y = 0, 3x + 4y = 5.
2x + 3y = 0 …eq.1
3x + 4y = 5 …eq.2
To solve these equations, we need to make one of the variables (in both the equations) have same coefficient.
Lets, multiply eq.1 by 3 and eq.2 by 2, so that variable x in both the equations have same coefficient.
Recalling equations 1 & 2,
2x + 3y = 0 [×3
3x + 4y = 5 [×2
⇒ 6x + 9y = 0
6x + 8y = 10
On solving the two equations we get,
y = - 10
Substitute y = - 10 in eq.1/eq.2, as per convenience of solving.
Thus, substituting in eq.1, we get
2x + 3( - 10) = 0
⇒ 2x = 30
⇒ x = 15
Hence, we have x = 15 and y = - 10.
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