Function Rule:

Question

f(x)= 2 + 7x

Student 1:
f(-1)= 2 + 7 (-1)
f(-1)= 9 (-1)
f(-1)= -9

Student 2:
f(-1)= 2 + 7 (-1)
f(-1)= 2 - 7
f(-1)= -5

One student is incorrect. Analyze their work to determine which students work is incorrect and describe the mistakes made.

Answer 1

Student 2 is incorrect in their calculation. The mistake occurs when they subtract 7 from 2 instead of adding 7. The correct calculation should be:

f(-1) = 2 + 7(-1)
f(-1) = 2 - 7
f(-1) = -5

Therefore, Student 2 made the mistake by subtracting instead of adding 7 in the second step.