Question

1. Find the value of the following
expressions for the given values.
a) x + 6 when x = -2 .
b) 1 - a - b when a = -1 and b = 2
c) x + x2 + x + 5 when x = -3
d) 4x - 5(3x + 1) when x = 2​

Answer 1

We have to find the values in the given expression and the values which have to be put is given

So, solving them

a) x + 6 when x = -2

Here, in the place of x we have to write -2

→ x + 6

→ -2 + 6

→ 4

b) 1 - a - b when a = -1 and b = 2

Here, in place of a we have to write -1 & in place of b we have to write 2

→ 1 - a - b

→ 1 - (-1) - 2

→ 1 + 1 - 2

→ 2-2

→ 0

c) x + x2 + x + 5 when x = -3

Here, in the place of x we have to write -3

→ -3 + (-3)² + (-3) + 5

→ -3 + 9 - 3 + 5

→ -6 + 9 + 5

→ -6 + 14

→ 8

d) 4x - 5(3x + 1) when x = 2

Here, in the place of x we have to write 2

→ 4x - 5(3x +1)

→ 4 × 2 - 5(3×2 + 1)

→ 8 - 5(6+1)

→ 8 - 5 × 7

→ 8 - 35

→ -27

Answer 2

Answer

a) Substituting the value of x = -2 :-

x + 6 = -2 + 6

= 4

b) Substituting the value of a = -1 and b = 2 :-

1 - (-1) - 2 = 1 + 1 - 2

= 0

c) Substituting the value of x = -3 :-

x + x2 + x + 5 = -3 + (-3)^2 - 3 + 5

= -3 + 9 - 3 + 5

= -6 + 9 + 5

= 3 + 5

= 8

d) Substituting the value of x = 2 :-

4x - 5 (3x + 1)

= 4 × 2 - 5 ( 3 × 2 + 1 )

= 8 - 5 ( 7 )

= 8 - 35

= -27