Final answer:
The addition of +70 and +80 in 2's complement 8-bit representation is incorrect because the sum causes an overflow. The result provided misrepresents a sum that exceeds the range of an 8-bit signed integer.
Step-by-step explanation:
The addition of +70 (01000110) and +80 (01010000) in 2's complement 8-bit representation is incorrect in the presentation given.
The correct process of adding these two numbers would lead to a different result because the sum exceeds the maximum value that can be represented in an 8-bit signed number, which causes an overflow. In binary addition, we add each bit from right to left, carrying over any bit that exceeds the value of 1 in a single column.
The result of adding +70 and +80 goes beyond the range of an 8-bit signed integer (which is -128 to +127), resulting in an overflow error. The presence of '1' as the leftmost bit in the given outcome (10010110) would signify a negative number in 2's complement, which is clearly not the expected result of adding two positive numbers.