Question 1023068
x, price for one pen
y, price for one pad


{{{system(10x+15y=26,5x+10y=16)}}}-----same as the system you found.


Your work appears to be the use of Elimination Method, at least part of the way.  Multiply the 16 equation by 2:
{{{system(10x+15y=26,10x+20y=32)}}}----the equivalent system.


Add the opposite of the 26 equation to the 32 equation.
{{{-(10x+15y)+(10x+20y)=-26+32}}}
{{{5y=6}}}
{{{highlight(y=6/5)}}}, which means {{{y=1&1/5}}}, or $1 20cents for one pad of paper.



Now what is x?
Go to either of the ORIGINAL equations to find x.  Now you know y.
{{{10x+15y=26}}}
{{{10x=26-15y}}}
{{{10x=26-15(6/5)}}}
{{{10x=26-3*6}}}
{{{10x=26-18}}}
{{{10x=8}}}
{{{5x=4}}}
{{{highlight(x=4/5)}}}--------which means 80 cents for a pencil.