10th mathematics exercise questions with answers

# Quadratic Equations Exercise 9.9 – Class X

### Quadratic Equations – Exercise 9.9 – Question:

1. Draw the graphs of the following quadratic equations:

(i) y = – x2

(ii) y = 3x2

(iii) y = 1/2 x2 – 2

(iv) y = x2 – 2x

(v) y = x2 – 8x + 7

(vi) y = (x + 2)(2 – x)

(vii) y = x2 + x – 6

(viii) y = x2 – 2x + 5

## Quadratic Equations – Exercise 9.9 – Solution:

1. Draw the graphs of the following quadratic equations:

(i) y = – x2

Solution:

 x -3 -2 -1 0 1 2 3 y -9 -4 -1 0 -1 -4 -9

(ii) y = 3x2

Solution:

 x -2 -1 0 1 2 y 12 3 0 3 12

(iii) y = 1/2 x2 – 2

Solution:

 x -2 -1 0 1 2 y 0 –3/2 -2 –3/2 0

(iv) y = x2 – 2x = x(x – 2)

Solution:

 x -2 -1 0 1 2 3 y 8 3 0 -1 0 3

(v) y = x2 – 8x + 7

Solution:

 x -1 0 1 2 3 4 5 6 7 8 9 y 16 7 0 -5 -8 -9 -8 -5 0 7 16

(vi) y = (x + 2)(2 – x)

Solution:

y = (x + 2)(2 – x) = 2x – x2 + 4 – 2x = -x2 + 4

Therefore, y = -x2 + 4

 x -3 -2 -1 0 1 2 3 y -5 0 3 4 3 0 -5

(vii) y = x2 + x – 6

Solution:

 x -4 -3 -2 -1 0 1 2 3 y 6 0 -4 -6 -6 -4 0 6

(viii) y = x2 – 2x + 5

Solution:

 x -2 -1 0 1 2 3 4 y 13 8 5 4 5 8 13