Answer :

Sure, let's verify the expression [tex]\(a - (-b) = a + b\)[/tex] for the given values of [tex]\(a\)[/tex] and [tex]\(b\)[/tex].

### Part (i)
Given:
[tex]\(a = -17\)[/tex]
[tex]\(b = +15\)[/tex]

Let's calculate the left-hand side (LHS) and the right-hand side (RHS) to verify the equation.

#### LHS Calculation:
[tex]\[ a - (-b) = -17 - (-15) \][/tex]

Subtracting a negative is equivalent to adding the positive value, so:
[tex]\[ -17 - (-15) = -17 + 15 \][/tex]

#### RHS Calculation:
[tex]\[ a + b = -17 + 15 \][/tex]

Now let's perform the addition:
[tex]\[ -17 + 15 = -2 \][/tex]

So for both LHS and RHS:
[tex]\[ LHS: -17 - (-15) = -2 \][/tex]
[tex]\[ RHS: -17 + 15 = -2 \][/tex]

Since the LHS equals the RHS, the equation [tex]\( a - (-b) = a + b \)[/tex] holds true for [tex]\( a = -17 \)[/tex] and [tex]\( b = +15 \)[/tex].

### Part (ii)
Given:
[tex]\( a = 50 \)[/tex]
[tex]\( b = 21 \)[/tex]

Let's again calculate the LHS and RHS to verify the equation.

#### LHS Calculation:
[tex]\[ a - (-b) = 50 - (-21) \][/tex]

Subtracting a negative is equivalent to adding the positive value, so:
[tex]\[ 50 - (-21) = 50 + 21 \][/tex]

#### RHS Calculation:
[tex]\[ a + b = 50 + 21 \][/tex]

Now let's perform the addition:
[tex]\[ 50 + 21 = 71 \][/tex]

So for both LHS and RHS:
[tex]\[ LHS: 50 - (-21) = 71 \][/tex]
[tex]\[ RHS: 50 + 21 = 71 \][/tex]

Since the LHS equals the RHS, the equation [tex]\( a - (-b) = a + b \)[/tex] holds true for [tex]\( a = 50 \)[/tex] and [tex]\( b = 21 \)[/tex].

### Conclusion
We have verified that the equation [tex]\( a - (-b) = a + b \)[/tex] is true for both pairs of given values:
1. [tex]\( a = -17 \)[/tex], [tex]\( b = +15 \)[/tex]
2. [tex]\( a = 50 \)[/tex], [tex]\( b = 21 \)[/tex]

In both cases, the left-hand side (LHS) is equal to the right-hand side (RHS), confirming the validity of the equation.