Question

if 4a-7b=14 and 9a=7(a+b), then determine the value of ab

Answer 1

Answer:

a=7,b=2

Step-by-step explanation:

Given 4a-7b=14___(1)

9a=7(a+b)

9a=7a+7b

9a-7a-7b=0

2a-7b=0_____(2)

Subtract (2)by (1)

4a-7b-(2a-7b)=14-0

2a=14

a=7 put in (2)

14-7b=0

b=2

So

a=7,b=2

Answer 2

The value of ab is equal to 14.

Step-by-step explanation:

The given equations are:

4a - 7b = 14                     .......... (1)

and 9a = 7(a + b)

2a - 7b = 0                       .......... (2)

To determine the value of ab = ?

Subtracting (1) from (2), we

4a - 7b - (2a - 7b) = 14 - 0

⇒ 4a - 7b - 2a + 7b = 14

⇒ 2a = 14

⇒ a = 7

Put  a = 7 in equation (1), we get

2(7)-7b=0

⇒ 7b = 14

⇒ b = 2

∴ a = 7 and  b = 2

The value of ab = 7 × 2 = 14

Thus, the value of ab is equal to 14.