Question

Suppose a-b=0

Which one of these expressions equals a+b ?
Choose one answer

a.)-2b
b.)2a
c.)0
d.)-b^2
e.)a/b

Answer 1

b) 2a
If a-b is 0, they are the same number so if you add them it would be the same as multiplying it by 2

Answer 2

Answer: The correct option is (b) 2a.

Step-by-step explanation: We are given the following condition :

`a-b=0~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)`

We are to select the correct expression that equals (a + b).

From equation (i), we have

`a-b=0\\\\\Rightarrow a=0+b\\\\\Rightarrow a=b~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(ii)`

Therefore, we get

`a+b\\\\=a+a~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~[\textup{from equation (ii)}]\\\\=2a.`

Thus, a + b = 2a.

Option (b) is CORRECT.