Try each answer into the equation in place of x and y
2x +3y +4 = 15
A) x = 6, y = 3
2x + 3y +4 = 15 2(6) +3(3) +4 =___ (should equal 15 to be the answer) 12 + 9 + 4 = 25 The equation equals 25, not 15, so A is not the answer.
B) x = 3, y = 5
2x +3y +4 = 15 2(3) +3(5) +4 = ___ (Should equal 15 to be the answer) 6 +15 +4 = 25 The equation equals 25, not 15, so B is not the answer
C) x = 6, y = 4 2x +3y +4 = 15 2(6) +3(4) +4 =___ (should equal 15 to be the answer) 12 + 12 +4 = 28 The equation equals 28, not 15, so C is not the answer
D) x = 1, y = 3
2x +3y +4 =15 2(1) +3(3) +4 = ___ (should equal 15 to be the answer) 2 +9 +4 = 15 The equation equals 15 so this would be the answer
D (or the last option) x = 1, y = 3 is the answer to your question