Solve the first equation for 'y' and substitute that value in the SECOND equation to get 'x'
8x + 9y =48
9y = 48 - 8x
y= (48-8x)/9
then 12x + 15y = 21
12x + 15 (48-8x)/9 = 21
12x + 80 -13.33333x = 21
1.33333x = 59
x=44.25 y=(48-8x)/9 = -34
Solve the following system:
{8 x+9 y = 48 | (equation 1)
12 x+15 y = 21 | (equation 2)
Swap equation 1 with equation 2:
{12 x+15 y = 21 | (equation 1)
8 x+9 y = 48 | (equation 2)
Subtract 2/3 × (equation 1) from equation 2:
{12 x+15 y = 21 | (equation 1)
0 x-y = 34 | (equation 2)
Divide equation 1 by 3:
{4 x+5 y = 7 | (equation 1)
0 x-y = 34 | (equation 2)
Multiply equation 2 by -1:
{4 x+5 y = 7 | (equation 1)
0 x+y = -34 | (equation 2)
Subtract 5 × (equation 2) from equation 1:
{4 x+0 y = 177 | (equation 1)
0 x+y = -34 | (equation 2)
Divide equation 1 by 4:
{x+0 y = 177/4 | (equation 1)
0 x+y = -34 | (equation 2)
Collect results:
Answer: |
| {x = 177/4
y = -34
