Let p be the prize of a pen and m the prize of a mechanical pencils. If you buy six pens and one mechanical pencil, you spend 6p+m. We know that this equals 9, because you get 1$ change from a 10$ bill.
Similarly, if you buy four pens and two mechanical pencils, you spend 4p+2m, which is 8$, because now you get a $2 change. Put these equation together in a system:

Now, if you multiply the first equation by 2, the system becomes

Subtract the second equation from the first:

Plug this value into the first equation to get

Answer:
Step-by-step explanation:
its true
Answer:
( f h ) (x) = 6 x² - 1
Step-by-step explanation:
<u><em>Step(i)</em></u>:-
Given<em> f(x) = 3 x - 4</em>
g (x) = −x²+2 x−5
<em> h (x) = 2 x² + 1</em>
j (x) = 6 x + 2 - 8 x
K (x) = 3 x² - x + 7
<u><em>Step(ii)</em></u>:-
<em>( f h ) (x) = f ( h (x)) = f ( 2 x² + 1 )</em>
= 3 (2 x² + 1 ) - 4
= 3 ((2 x² ) + 3 - 4
= <em>6 x² - 1</em>
<u><em> Final answer:</em></u>-
∴ <em> ( f h ) (x) = 6 x² - 1</em>