Question

When a=0,b=-1,
(i) 2a + 21​

Answer 1

Answer:

2×0+21=21

Step-by-step explanation:

why value of b is given ?

Answer 2

$a = 0 \: b = 1 \: \\ 2a + 21 = 2(0) + 21 \\ = 0 + 21 \\ = 21$