Question:
If x = – 1, y = 2 is a solution of the equation 3x + 4y = k, find the value of k.
Solution:
We are given, 3x + 4y = k
Given that, (-1, 2) is the solution of equation 3x + 4y = k.
Substituting x = -1 and y = 2 in 3x + 4y = k,
We get; 3x - 1 + 4 × 2 = k
K = - 3 + 8 k = 5