They may be equally long, but length when written is IMO not a good measure of complexity.
The 2nd I would need pen and paper for to keep my head straight doing the distributive law. The 1st I can do in my head as:
"If b is larger than a, the left side will be negative instead of positive, but also "b-a" gets a negative sign, and these cancel each other, so it is the same"
But I agree with you anyway ...this is indeed "doing algebra".
I agree that the figure would have been better if it said that in that figure it displays the case where a is larger than b. And we should probably call it visualization of an algebraic proof, instead of visual proof.
The 2nd I would need pen and paper for to keep my head straight doing the distributive law. The 1st I can do in my head as:
"If b is larger than a, the left side will be negative instead of positive, but also "b-a" gets a negative sign, and these cancel each other, so it is the same"
But I agree with you anyway ...this is indeed "doing algebra".
I agree that the figure would have been better if it said that in that figure it displays the case where a is larger than b. And we should probably call it visualization of an algebraic proof, instead of visual proof.