JAMB - Mathematics (2025 - No. 3)
Solve the simultaneous equation \(\frac{\text{x}}{2}\) - \(\frac{\text{y}}{5}\) = 1 and y - \(\frac{\text{x}}{3}\) = 8
x = 10, y = -6
x = 10, y = 6
x = 6, y = 10
x = 10, y = 6
Explanation
\(\frac{\text{x}}{2}\) - \(\frac{\text{y}}{5}\) = 1 - - - - - - 1
y - \(\frac{\text{x}}{3}\) = 8 - - - - - 2
We clear the fractions by multiplying through by the lcm of 2 and 5 = 10 for eqn 1 and 3 for eqn 2
5x - 2y = 10 - - - - - - - 3
3y - x = 24 - - - - - - - - - 4
from eqn 4, make x the subject of formula
x = 3y - 24 (after multiply thru by -1, so x can be positive)
Put x = 3y - 24 into eqn 3
5(3y - 24) - 2y = 10
15y - 120 - 2y = 10
15y - 2y = 10 + 120
13y = 130
y = \(\frac{130}{13}\) = 10
y = 10 put in eqn 4
3y - x = 24 - - - - - - - - - 4
3(10) - x = 24
30 - x = 24
- x = 24 - 30 = -6
x = 6 ( minus cancels out minus)
Therefore, x = 6, y = 10.
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