Answer:
1. u = 2, v = -1.5
2. y = -7, x = -3
Step-by-step explanation:
1) For the following simultaneous equation, we have;
5·u + 2·v = 7....................(1)
2·u - 2·v = 7......................(2)
Adding equation (1) to equation (2), gives;
5·u + 2·v + 2·u - 2·v = 14
5·u + 2·u + 2·v- 2·v = 14
7·u = 14
u = 14/7 = 2u = 2
u = 2
From equation (1), we have;
5·u + 2·v = 7 substituting u = 2 gives;
5×2 + 2·v = 7
2·v = 7 - 5×2 = 7 - 10 = -3
v = -3/2 = -1.5
v = -1.5
2.
3·x - 4·y = 19....................(1)
4·x - 5·y = 23.......................(2)
Multiplying equation (1) by 4 and equation (2) by 3 gives;
For equation (1)
4 × (3·x - 4·y) = 4 ×19
12·x - 16·y = 76...........................(3)
For equation (2)
3 × (4·x - 5·y) = 3 × 23
12·x - 15·y = 69...........................(4)
Subtracting equation (3) from equation (4) gives;
12·x - 15·y - (12·x - 16·y) = 69 - 76 = -7
12·x - 15·y - 12·x + 16·y = 69 - 76 = -7
12·x - 12·x - 15·y + 16·y = -7
y = -7
Substituting the value of y = -7 in equation (1), we have;
3·x - 4·y = 19 = 3·x - 4×(-7) = 19
3·x - 4×(-7) = 19
3·x + 28 = 19
3·x = 19- 28 = -9
x = -9/3 = -3
x = -3.
