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If the pair of linear equations 2x+3y=72x + 3y = 7 and 2px+(p+q)y=28 2px + (p + q) y = 28 has an infinite number of solutions, then (p, q)

Solution

✅ Correct Option: 2

For infinite solutions, the equations must be proportional.

Given equations:

2x+3y=72x + 3y = 7 ...(1)

2px+(p+q)y=282px + (p+q)y = 28 ...(2)

For infinite solutions, coefficients must be proportional:

22p=3p+q=728\frac{2}{2p} = \frac{3}{p+q} = \frac{7}{28}

From 728=14\frac{7}{28} = \frac{1}{4}:

22p=14\frac{2}{2p} = \frac{1}{4}

p=4p = 4

And 3p+q=14\frac{3}{p+q} = \frac{1}{4}

34+q=14\frac{3}{4+q} = \frac{1}{4}

3=4+q3 = 4+q

q=8q = 8

Therefore (p,q)=(4,8)(p,q) = (4,8)

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