Question

4. Find the value of:
(i) 6x2 - 5x + 4, when x = 5.
(ii) 3x2 - 4x - 2, when x = -4.
(iii) 2x - 3x2 + 5x + 6, when x = 3. (iv) ** -- 2x3 + x2 - 7x - 10, when x = -2.​

Answer 1

Question Asked:

1. 6 × 2 - 5x + 4, when x = 5
2. 3 × 2 - 4x - 2, when x = -4
3. 2x - 3 × 2 + 5x + 6, when x = 3
4. 2 × 3 + 2 - 7x - 10, when x = -2.​

Step-by-step explanation:

1)6 × 2 - 5x + 4, when x = 5

  12 - 5(5) + 4 = 12 - 25 +4

  = 12 - 21 = -9

2) 3 × 2 - 4x - 2, when x = -4

   6 - 4(-4) - 2 = 6 - (-16) - 2 = 20

3) 2x - 3 × 2 + 5x + 6, when x = 3

   2(3) - 6 + 5(3) + 6 = 6 - 6 + 15 +6 = 21

4) 2 × 3 + 2 - 7x - 10, when x = -2  

    6 + 2 -7(-2) - 10 = 6 + 2 + 14 - 10 = 12

Answer:

1. -9
2. 20
3. 21
4. 12

Answer 2

Answer:

i) 6×2-5x+4 x=5

put, x=5

6×2-5x+4

12-5 (5)+4

12- 25 +4

13 + 4

17

x = 17

(ii) 3x2 - 4x -2

put , x= -4

3 × 2 - 4 (-4) -2

3 × 2 - 8 - 2

6 - 8 - 2

6 - 10

-4

x = -4

iii) 2x -3x2 + 5x + 6

put , x = 3

2 (3) - 3 × 2 + 5 + 6

6 - 6 + 11

6 + 5

11

x = 11

iv) 2 × 3 + x2 -7x - 10

x = -2

put , x = -2

2 × 3 + (-2) 2 - 7 ( -2 ) -10

6 + (-4) + 14 - 10

2 + 4

6

x = 6