Question

6a-3b+2c when a=1, b=-1 and c=2

Answer 1

Question : Find value of 6a - 3b + 2c

Values given :

a = 1

b = -1

c = 2

Answer :

➥ Substitute values of variables

6a - 3b + 2c = 6(1) - 3(-1) + 2(2)

                    = 6 - (-3) + 4

                    = 6 + 3 + 4

                    = 13

∴ The value of 6a - 3b + 2c = 13

Answer 2

Answer:

$\huge\underbrace\mathfrak\orange{AnSWer}$

Here, a = 21,

d = 18 – 21 = – 3

and

an = – 81, and we have to find n.

As an = a + ( n – 1) d,

we have;

– 81 = 21 + (n – 1)(– 3)

– 81 = 24 – 3n

– 105 = – 3n

So, n = 35

Therefore, the 35th term of the given AP is – 81.

Next, we want to know if there is any n for which an = 0.

If such an n is there, then;

21 + (n – 1) (–3) = 0,

3(n – 1) = 21

n = 8

Therefore, the eighth term is 0.