Answer:
1. To eliminate x-term, multiply the second by -2
2. To eliminate y-term, multiply the second by 3
Explanation:
4x - 9y = 7 (1)
-2x + 3y = 4 (2)
1. To eliminate x-term, multiply the second by -2
-2x + 3y = 4 (2) × 2
-4x + 6y = 8 (3)
4x - 9y = 7 (1)
Add (3) and (1)
6y - 9y = 8 + 7
-3y = 15
y = 15/-3
y = -5
4x - 9y = 7 (1)
4x - 9(-5) = 7
4x + 45 = 7
4x = 7 - 45
4x = -38
x = -38/4
x = -9.5
4x - 9y = 7 (1)
-2x + 3y = 4 (2)
2. To eliminate y-term, multiply the second by 3
-2x + 3y = 4 (2) × 3
-6x + 9y = 12 (3)
4x - 9y = 7 (1)
-6x + 4x = 12 + 7
-2x = 19
x = 19/-2
x = -9.5
4x - 9y = 7 (1)
4(-9.5) - 9y = 7
-38 - 9y = 7
-38 - 7 = 9y
-45 = 9y
y = -45/9
y = -5