JAMB 1985 · UME · Q24

Linear & simultaneous equations

Solve the simultaneous equations $2x - 3y + 10 = 10x - 6y = 5$ .

Worked solution (try it first)

Each part of the chain equals 5.
From $2x - 3y + 10 = 5$ , take 10 from both sides: $2x - 3y = -5$ .
The other part gives $10x - 6y = 5$ .
Double the first equation: $4x - 6y = -10$ .
Subtract it from $10x - 6y = 5$ so $y$ cancels: $6x = 15$ , so $x = 2\frac12$ .
Then $3y = 2x + 5 = 10$ , so $y = 3\frac13$ .
The answer is option A.

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