Answer:
b = (7, -9)
Step-by-step explanation:
Let a = (-3,4) and v = (4,-5).
If a + b = v. find b.
performing the addition of the vectors would mean that we add corresponding coordinates.
so
let b = (x, y)
then a + b = (-3, 4) + (x, y) = (-3 + x, 4+y) = v = (4, -5)
-3 + x = 4
4 + y = -5
x = 7
y = -5 - 4 = -9
so b = (7, -9)