5+5:{[5+5x(x-5)]:5-5}-5:5=5
5+5:{[5+5x(x-5)]:5-5}-1=5
5+5:{[5+5x(x-5)]:5-5}=5+1
5+5:{[5+5x(x-5)]:5-5}=6
5:{[5+5x(x-5)]:5-5}=6-5
5:{[5+5x(x-5)]:5-5}=1
[5+5x(x-5)]:5-5=5×1
[5+5x(x-5)]:5-5=5
[5+5x(x-5)]:5=5+5
[5+5x(x-5)]:5=10
5+5x(x-5)=10×5
5+5x(x-5)=50
5x(x-5)=50-5
5x(x-5)=45
x-5=45:5
x-5=9
x=9+5
x=14