Question

If 2a2+b2-2ab+6a+9 then find the value of a+b+ab

Answer 1

Given, a+b=5and a−b=3adding the above two equation, 2a=8a=4Putting this value of a in any of the above equation we get, b=5−4=1Now we have to find out, a2+ab2−a2b2=42+4×12−42×12=16+4−16=4

Answer 2

$2a^2+b^2-2ab+6a+9$ = 58

Step-by-step explanation:

Given,

a + b  = 5               ........... (1)

and a − b = 3          ........... (2)

To find, the value of $2a^2+b^2-2ab+6a+9$ = ?

Adding equations (1) and (2), we get

a + b + a − b = 5 + 3

⇒ 2a = 8

⇒ a = 4

Put a = 4 in equation (1), we get

4 + b  = 5  

⇒ b = 5 - 4 = 1

∴ $2a^2+b^2-2ab+6a+9$

$= 2(4)^2+1^2-2(4)(1)+6(4)+9$

= 2(16) + 1 - 8 + 24 + 9

= 32 + 34 - 8

= 66 - 8

= 58

∴ $2a^2+b^2-2ab+6a+9$ = 58