Stanley attempted to simplify the expression below.
β4β(2.5xβ1.25)β3x
His work, step by step, is shown below.
Step 1: β4β{(2.5x+(β1.25)}β3x
Step 2:β10x+(β5)β3x
Step 3:β10xβ3x+(β5)
Step 4: β13xβ5
In which step did he make his first error simplifying the expression?