Question

plz solve this sum ​

Answer 1

Step-by-step explanation:

a+b=5

a-b=4

So adding these

2a=9

a=9/2

Putting a=9/2 in any of the eq

9/2+b=5

b=1/2

1)a^2+b^2=(9/2)^2+(1/2)^2=81/4+1/4=82/4=41/2

2)ab= 9/2x1/2=9/4

Answer 2

Step-by-step explanation:

we have two equation

:- a+b =5 and a-b=4

$a = 5 - b \: \: ...............(i)$

now put the value of a on second equation

$5 - b - b = 4 \\ - 2b = - 1 \\ b = \frac{1}{2}$

now we find value of b ..then put the value of b on second equation

$a = 5 - \frac{1}{2} \\ a = \frac{10 - 1}{2} \\ a = \frac{9}{2}$

we have find value of a and b

1) a² + b²

$\implies( \frac{9}{2} ) {}^{2} +( \frac{1}{2} ) {}^{2} \\ \implies \frac{81}{4} + \frac{1}{4} \\ \implies \frac{82}{4}$

2) ab

$\implies \frac{9}{2} \times \frac{1}{2} \\ \implies \frac{9}{4}$