ANSWER
The short piece is 10 meters long and the long piece is 33 meters long
Step-by-step explanation
Let the length of the shorter piece be x.
Let the length of the longer piece be y.
We have that the total length of the banner is 43 meters. This means that:
x + y = 43 ___(1)
The short piece is 23 meters shorter than the long piece. This means that:
x = y - 23 _____(2)
Now, we have a system of two simultaneous equations:
x + y = 43
x = y - 23
We can solve this by substitution.
Substitute the second equation into the first equation.
That is:
y - 23 + y = 43
Collect like terms:
y + y = 43 + 23
2y = 66
Divide through by 2:
y = 66 / 2
y = 33 m
Recall that:
x = y - 23
Therefore:
x = 33 - 23
x = 10 m
Therefore, the short piece is 10 meters long and the long piece is 33 meters long.