Question

a) Complete the table of values for y=1/4x^3-x^2+2

b) which of a , b or c is the correct curve for y=1/4 x^3-x^2+2

Answer 1

Answer:

a) 1.25  , 2

b)  A

Step-by-step explanation:

a) x=1    y = 1/4 x1³ - 1² + 2 = 1 1/4 = 1.25

   x=4   y = 1/4 * 64 - 16 + 2 = 2

b)  curve A

Answer 2

Answer:

a) i) when x = -2, y = -4

ii) when x = -1, y = 0.75

iii) when x = 1, y = 1.25

iv) when x = 4, y = 2

b) graph A

Step-by-step explanation:

$y = \frac{1}{4} {x}^{3} - {x}^{2} + 2$

1) when x = -2,

* substitute -2 into x

$y = \frac{1}{4} {( - 2)}^{3} - {( - 2)}^{2} + 2$

$y = - 2 - 4+ 2$

$y = - 4$

2) when x = -1

* substitute -1 into x

$y = \frac{1}{4} {( - 1)}^{3} - {( - 1)}^{2} + 2$

$y = - \frac{1}{4} - 1 + 2$

$y = \frac{3}{4} \: or \: 0.75$

3) when x = 1

* substitute 1 into x

$y = \frac{1}{4} {( 1)}^{3} - {( 1)}^{2} + 2$

$y = \frac{1}{4} - 1 + 2$

$y = \frac{5}{4} \: or \: 1.25$

4) when x = 4

* substitute 4 into x

$y = \frac{1}{4} {( 4)}^{3} - {( 4)}^{2} + 2$

$y = 16 - 16 + 2$

$y = 2$