Karim is solving the quadratic equation x2+5x−24=0 by grouping. His work is shown below. Determine the first step at which Karim makes an error.
Step 1: x2+8x+(−3x)−24=0
Step 2: (x2+8x)+(−3x−24)=0
Step 3: x(x+8)+3(x+8)=0
Step 4: (x+8)(x+3)=0
Step 5: x+8=0 or x+3=0
x=−8 or x=−3
(1 point)
Karim's first mistake occurs at Step
.