solve for x and y by elimination method:- . . . .
. . 0.4 x -1.5 y=6.5 and 0.3 X + 0.2y=0.9.
Answers
Answer:
ok.
6x - 9y = 19.5
7y - 2x = -8.5
Multiply the second equation by 3,
6x - 9y = 19.5
21y - 6x = -25.5
Add the two equations side by side to eliminate x,
6x - 9y + 21y - 6x = 19.5 - 25.5
12y = -6
y = -0.5
Now substitude y = -0.5 into the first equation to get x,
6x - 9y = 19.5
6x - 9(-0.5) = 19.5
6x + 4.5 = 19.5
6x = 15
x = 2.5
0.3x - 0.2y = 4
0.4x + 0.3y = 5/19
Multiply the first equation by 3 and the second equation by 2,
0.9x - 0.6y = 12
0.8x + 0.6y = 10/19
Add the two equations side by side to eliminate y,
0.9x - 0.6y + 0.8x + 0.6y = 12 + 10/19
1.7x = 238/19
x = 140/19
Now substitude x = 140/19 into the first equation to get y,
0.3x - 0.2y = 4
0.3(140/19) - 0.2y = 4
42/19 - 0.2y = 4
y = -170/19
0.05x + 0.02y = 11
0.15x + 0.05y = 12
Multiply the first equation by -3,
-0.15x - 0.06y = -33
0.15x + 0.05y = 12
Add the two equations side by side to eliminate x,
-0.15x - 0.06y + 0.15x + 0.05y = -33 + 12
-0.01y = -21
y = 2100
Now substitude y = 2100 into the first equation to find x,
0.05x + 0.02y = 11
0.05x + 0.02(2100) = 11
0.05x + 42 = 11
x = -620
Answer: x = 5 & y = -3
Hope it helps