Question

Please help :')

Answer 1

Let

x---------> represents Martin's sister's age

y--------> represents Martin's  age

we know that

$y=x-6$ --------> equation $1$

$x+y\leq 22$ --------> equation $2$

Substitute equation $1$ in equation $2$

$x+[x-6]\leq 22\\2x\leq 22+6\\ x\leq 14$

therefore

the answer is

Part a) An inequality that can be used to represent this situation is

$x+[x-6]\leq 22$ or $x\leq 14$

Part b) the oldest age Martin's sister can be is $14$ years old

Answer 2

X - 6 + x < 22
2x < 28
x<28/2
x<14

The answer is x<14 (Martin's sister is less than 14 years old)