Lagrange multipliers:







(if

)

(if

)

(if

)
In the first octant, we assume

, so we can ignore the caveats above. Now,

so that the only critical point in the region of interest is (1, 2, 2), for which we get a maximum value of

.
We also need to check the boundary of the region, i.e. the intersection of

with the three coordinate axes. But in each case, we would end up setting at least one of the variables to 0, which would force

, so the point we found is the only extremum.
She will pay 90 because the income is 5 times greater
(answer o number one)
The coefficient in (2/3q-3/4) is 2/3 and in (-1/6q-r) is -1/6
25% chance because there are 8 total “slices” and there are 2 A’s.
2/8=1/4=25%
Yes. It is equivalent to 3. Combine like terms