Answer:
if you divide both sides of -5x > 0 you get z > <em>0. </em>This is incorrect because if you choose a value from the possible solutions such as z=6 and substitute it into the original equation you get <em>-30</em> > 0, which is <em>not true</em>
I put the answers in bold
hope this helps!
Step-by-step explanation:
There is a similar shortcut for multiplying decimal numbers by numbers such as 10, 100, and 1000: Move the decimal point to the right as many places as there are zeros in the factor. Move the decimal point one step to the right (10 has one zero). Move the decimal point two steps to the right (100 has two zeros).
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Answer:
The answere is C
Step-by-step explanation:
Multiply both sides of the second equation by 100 to get rid of the decimals:
0.05<em>n</em> + 0.10<em>d</em> = 1.50
==> 5<em>n</em> + 10<em>d</em> = 150
Multiply both sides of the first equation by -5:
<em>n</em> + <em>d</em> = 21
==> -5<em>n</em> - 5<em>d</em> = -105
Add the two equations together:
(5<em>n</em> + 10<em>d</em>) + (-5<em>n</em> - 5<em>d</em>) = 150 + (-105)
Notice that the terms containing <em>n</em> get eliminated and we can solve for <em>d</em> :
(5<em>n</em> - 5<em>n</em>) + (10<em>d</em> - 5<em>d</em>) = 150 - 105
5<em>d</em> = 45
<em>d</em> = 45/5 = 9
Plug this into either original equation to solve for <em>n</em>. Doing this with the first equation is easiest:
<em>n</em> + 9 = 21
<em>n</em> = 21 - 9 = 12
So Donna used 12 nickels and 9 dimes.
