Question

if a system has an infinite number of solutions, use set-builder notation to write the solution set. If a system has no solution, state this.
3x + 4y = 5,
2x + y = 1

Answer 1

3x + 4y = 5,...........................................(1)
2x + y = 1 * by 4
8x + 4y = 4.............................................(2)
subtract: (2) - (1)
5x = -1
x = -1/5
plug x = -1/5 in (1)
-3/5 + 4y = 5
y = 5.6 / 4 = 1.4

solution is (-0.2,1.4)