Question

A+B=100
A-B=70
A=?
B=?

Answer 1

$\huge{\mathcal{\blue{Answer}}}$

Using substituting method:

$\large{A+B=100.....(1)}$

$\large{A-B=70.....(2)}$

Soling eq (1)

$a + b = 100 \\ a =100 - b........(3)$

Substituting in(2)

$a - b = 70 \\ 100 - b - b = 30 \\ 100 - 2b = 30 \\ - 2b = 30 - 100 \\ - 2b = - 70$

$\huge{\mathcal{\blue{B=35}}}$

Substituting in (3) we get

$a = 100 - b \\ a = 100 - 35$

$\huge{\mathcal{\blue{A=65}}}$

Answer 2

$\huge\underline\mathfrak\blue{Solution}$

Refer to the attachment!!