Question

Solve: 7x + 11y = 1, 8x + 13y = 2

• A. x = - 5, y = 3
• B. x = -7, y = 2
• C. x = -3, y = 2
• D. Insufficient data
• E. None of the above

Answer 1

The correct option is C x = -3, y = 2

7x + 11y = 1 ....... (1)
8x + 13y = 2 ....... (2)
Multiplying Equation (1) and Equation (2) by 8 and 7 resepectively, we have
56x + 88y = 8 and 56x + 91y = 14
Subtracting the second equation from the first, we get
-3y = -6, i.e., y = 2
From Equation (1), $x=\frac{1-11\left(y\right)}{7}=\frac{1-11\left(2\right)}{7}=-3$
$\therefore$ x = -3 and y = 2