Question

(b) If 2x+3y = 8 and xy=2 find the value of 2x-3y​

Answer 1

Answer:

Step-by-step explanation:

Answer:

Step-by-step explanation:

they have given that xy = 2

                                   x = 2/y

now sub it in the equation 2x + 3y = 8

= 2x + 3y = 8

= 2 x 2/y + 3y = 8

= 4/y + 3y = 8

=4 + 3y² / y = 8

4 + 3y² = 8y

4 + 3y² - 8y =0

3y² - 8y + 4 = 0

3y² - 6y - 2y + 4 =0

3y ( y - 2) -2(y-2)= 0

y = 2 or y = 2/3

now case (1) y = 2

x = 2/ y

x = 2/2= 1

x=1

now 2x-3y

= 2 - 6

= -4

now case(2) y=2/3

x = 2/2/3

x = 3

now 2x-3y

= 2 x 3 - 3 x 2/3

= 6 - 2

= 4

now the value is -4 (or) 4