Question

If a+b=‐1  and –a+b=3. Then adding both the equations , the value of b is ______

A)    ‐1                                    B)  1                                         C) ‐2                                  D) 2​

Answer 1

Answer:

The value of b is 1

From a+b= -1, I we get

a= -1 -b

putting the value of a in -a + b = 3, we get

1+b + b =3

2b=3-1

b = 2/2

b = 1

Answer 2

Step-by-step explanation:

a+b=(‐1)--eq1

(-a)+b=3--eq2

Add eq1 and eq2, we get

(-2a)=4

(-2a)=4

a=4/(-2)

a=(-2)

Substituting a=2 in eq1

a+b=(‐1)

(-2)+b=(-1)

b=(-1)+2

b=1

Therefore, option B is correct.