15c SOLVE question on usage

[lemontea]

Thanks! That helps a lot. BUT I don't understand this bit:

(examples as per that web page; deleted non-15c information here)

Quote:EXAMPLE:

f(x, y, z) = 2*x - ln y + 1/z

x in R1; y in R2; z in R3

LBL A
STO (i)
RCL 1
2
*
RCL 2
LN
-
RCL 3
1/x
+
RTN

In RUN mode, solve for x such that f(x, y=15.1, z=5.3) = 0

15.1
STO 2
5.3
STO 3
1
STO I
0.5
ENTER
5
SOLVE A

(Answer is 1.263007749)

Next, solve for y such that f(x=0.7, y, z=3.3) = 0

0.7
STO 1
3.3
STO 3
2
STO I
0.5
ENTER
6
SOLVE A

(Answer is 5.490560270)

Why did the example have to enter the last 2 values before executing SOLVE? (the 0.5 and the 5; and then later the 0.5 and 6).

Quote:0.5
ENTER
5
SOLVE A