Answer:
The length of the longer piece will be [tex]39\ cm[/tex]
Step-by-step explanation:
Let
x------> the longer piece
y-----> the shorter piece
we know that
[tex]x+y=63[/tex] ------> equation A
[tex]x=y+15[/tex] ------> equation B
substitute the equation B in equation A
[tex](y+15)+y=63[/tex]
solve for y
[tex]2y=63-15[/tex]
[tex]y=48/2=24\ cm[/tex]
Find the value of x
[tex]x=y+15[/tex]--------> [tex]x=24+15=39\ cm[/tex]