Question

4. When x = 3, y = 5 find the value of
(a) x³- y³
(b) 3x²y + 2xy – xy²​

Answer 1

Answer:

a)-98

Step-by-step explanation:

a)27-125

= -98

hoping it helped you

Answer 2

Answer:

a) x^3 - y^3

= 3^ - 5^3

So a^3 - b^3 = (a-b) (a^2 + ab + b^2)

After substituting we get :

                               = (3-5) (9 + 3 x 5 + 25)

                               = (-2) ( 9 + 15 + 25)

                               = (-2) ( 49 )

                               = - 98  

b) 3x^2y + 2xy - xy^2

= 3(9)^2(5) + 2x3x5 - 3x(5)^2

= 3 x 81 x 5 + 30 - 3 x 25

= 243 x 5 + 30 - 75

= 1215 + 30 - 75

= 1245 - 75

= 1170