The first one would be C and the 2nd is A.
Answer:
x = -7
Step-by-step explanation:
f(x) = -2x + 9
f(x) = 23
therefore, f(x) =
-2x + 9 = 23
-2x = 23 - 9
-2x = 14
-x = 14 ÷ 2
-x = 7
x = -7
The second one on the top right
![\dfrac\partial{\partial y}\left[e^{2y}-y\cos xy\right]=2e^{2y}-\cos xy+xy\sin xy](https://tex.z-dn.net/?f=%5Cdfrac%5Cpartial%7B%5Cpartial%20y%7D%5Cleft%5Be%5E%7B2y%7D-y%5Ccos%20xy%5Cright%5D%3D2e%5E%7B2y%7D-%5Ccos%20xy%2Bxy%5Csin%20xy)
![\dfrac\partial{\partial x}\left[2xe^{2y}-y\cos xy+2y\right]=2e^{2y}+y\sin xy](https://tex.z-dn.net/?f=%5Cdfrac%5Cpartial%7B%5Cpartial%20x%7D%5Cleft%5B2xe%5E%7B2y%7D-y%5Ccos%20xy%2B2y%5Cright%5D%3D2e%5E%7B2y%7D%2By%5Csin%20xy)
The partial derivatives are not equal, so the equation is not exact.
Answer:
x/4<-1
Quotient means division so x should be divided by four