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प्रश्न
Solve each of the following systems of equations by the method of cross-multiplication
3x + 2y + 25 = 0
2x + y + 10 = 0
उत्तर
The given system of equation is
3x + 2y + 25 = 0
2x + y + 10 = 0
Here
`a_1 = 3, b_1 = 2, c_1 = 25`
`a_2 = 2, b_2 = 1, c_2 = 10`
By cross-multiplication, we have
`=> x/(2xx 10-25xx 1) = (-y)/(3xx 10- 25xx 2) = 1/(3xx1 - 2xx2)`
`=> x/(20-25) = (-y)/(30-50) =- 1/(3-4)`
`=> x/(-5) = (-y)/(-20) = 1/(-1)`
Now `x/(-5) = 1/(-1)`
`=> x = (-5)/(-1) = 5`
And
`(-y)/(-20) = 1/(-1)`
`=> y/20 = 1`
=> y = -20
Hence, x = 5, y = 20 is the solution of the given system of equations.
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