Well, the answer to the question in your picture is $1200.
If x is the original price, and we took 23%, or 0.23 from that, we are left with 77%, or 0.77 of the full price.
So 0.77x = 924
x = 924/0.77
x = 1,200
1200 - 0.23(1200) = 924
924 = 0.77x
They probably want 880 pesos, since they asked you do intermediate rounding
but a more accurate answer would be
883.20 pesos
To combine the functions, you'd substitute in 2.76r for y in 0.16y. This would give you 0.16(2.76r), which simplifies to 0.4416r, but they want you round this to the nearest hundredth, so its really 0.44r. Substitute in the 2000 for r and you get 0.44 * 2000 which is 880 pesos
Obtuse angle
Operation
Order of operation