Answer:
See explanations below
Step-by-step explanation:
Given the simultaneous equations;
2x - 3y = 9... 1
2x + y = 13 ... 2
From 2;
y = 13-2x
Substitute into 1;
2x - 3(13-2x) = 9
2x -39 + 6x = 9
8x - 39 = 9
8x = 9+39
8x = 48
x = 6
Since y = 13-2x
y = 13-2(6)
y = 13-12
y = 1
The soluton to the system of equation is (6, 1)
Given the equations;
99x + 101y = 499; .... 1 * 101
101x + 99 y = 501 ... 2 * 99
______________
9999x + 10,201y = 50,399
9999x + 9801y = 49,599
Subtract
10201y - 9801y = 50399-49599
400y = 800
y = 2
Substitute y = 2 into 1;
From 1;
99x + 101y = 499
99x + 101(2) =499
99x +202 = 499
99x = 499 - 202
99x = 198
x = 198/99
x =2
Hence the solution is (2,2)
For the equations;
49x - 57y = 172 .... * 57
57x - 49y = 252 __ * 49
____________________
2793x -3249y = 9804
2793x - 2401y = 12348
Subtract
-3249y+2401y = 9804-12348
-848y = -2544
y = 3
Substitute into 1;
49x - 57y = 172
49x - 57(3) = 172
49x - 171 = 172
49x = 171+172
49x = 343
x = 7
Hence the solution is (7, 3)
