Question

Mark (✓) against the correct answer
What must be subtracted from −7 to obtain −15?

(a) −8
(b) 8
(c) −22
(d) 22

Answer 1

(b) 8
Suppose that a is subtracted from −7. Then, we have:

−7 − a = −15
a = −7 + 15 = 8

∴ 8 must be subtracted from −7 to obtain −15.