Answer:
23
Explanation:
let the number = X
subtracting 13 from X = X -13
multiplying the difference by -4= (X -13)×-4
the result is -40 means (X-13)×-4=-40
(X- 13)×-4 = -40
-4 X +52 = -40
collect like term
-4 X = -40-52
- 4X = -92
dividing bothsides by -4
-4 X /-4 = -92/-4
X = 23