4b-75=y 6b+45=y

4b-75=y 6b+45=y

Thanks Guest,

Our guest has done it by elimination method.  Which is good

I just thought it might be a little quicker by substitution method.

\(4b-75=6b+45\\ -2b=120\\ b=-60\\ \mbox{----}\\ y=4b-75\\ y=4*-60-75\\ y=-240-75\\ y=-315 \)

b=-60 and y=-315

Solve the following system:
{4 b-75 = y |     (equation 1)
6 b+45 = y |     (equation 2)
Express the system in standard form:
{4 b-y = 75 |     (equation 1)
6 b-y = -45 |     (equation 2)
Swap equation 1 with equation 2:
{6 b-y = -45 |     (equation 1)
4 b-y = 75 |     (equation 2)
Subtract 2/3 × (equation 1) from equation 2:
{6 b-y = -45 |     (equation 1)
0 b-y/3 = 105 |     (equation 2)
Multiply equation 2 by 3:
{6 b-y = -45 |     (equation 1)
0 b-y = 315 |     (equation 2)
Multiply equation 2 by -1:
{6 b-y = -45 |     (equation 1)
0 b+y = -315 |     (equation 2)
Add equation 2 to equation 1:
{6 b+0 y = -360 |     (equation 1)
0 b+y = -315 |     (equation 2)
Divide equation 1 by 6:
{b+0 y = -60 |     (equation 1)
0 b+y = -315 |     (equation 2)
Collect results:
Answer: | 
| {b = -60
y = -315