Question

Kiara found the solution for the inequality, 3.2 less-than negative 9.5 + x.

3.2 less-than negative 9.5 + x. 3.2 + 9.5 less-than negative 9.5 + 9.5 + x. 12.7 less-than x.
A number line going from 12 to 12.9. An open circle is at 12.7. Everything to the left of the circle is shaded.

What is Kiara’s error?
Kiara should have added 9.5 to each side of the inequality to get the solution 6.3 less-than x.
Kiara should have reversed the variable and the number in the solution to get x less-than 12.7.
Kiara should have used a closed circle on the graph.
Kiara should have shaded the number line to the right of the circle.

Answer 1

Answer: Kiara should have shaded the number line to the right of the circle.

Reason: 3.2 < −9.5 + x → add 9.5 to both sides → 12.7 < x (i.e. x > 12.7). The open circle at 12.7 is correct, but the region to the right (greater than 12.7) should be shaded, not the left.