Answer:
(x,y) = (2,3)
Step-by-step explanation:
y=5x-7 (i)
-3x-2y= -12
-(3x+2y)= -12
3x+2y= 12 (ii)
By putting the value of y from (i) in (ii)
3x+2(5x-7)=12
3x+10x-14=12
13x=12+14
13x= 26
x = 
x= 2
By putting the value of x in (i)
y= 5(2)-7
y= 10-7
y= 3
(x,y) = (2,3)
2 to the 8th power = 512
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Answer:
4th and 5th option
Step-by-step explanation:
you can easily add eqn 1 and 2 to get rid of the y term for 4th option and get rid of x term by addition as well for the 5th option
this is a topic on simultaneous equation. If you wish to explore more into this topic you can give me a follow on Instagram (learntionary) I'll be posting the notes for this topic and some other tips :)
So, I didn't quite understand your question clearly, but I'll try my best to answer it.
So, the first question is quite simple: Did the runner have a % decrease in his time or an increase.
Well, 7:45 is minor than 5:51. So, his time decreased.
2nd question:
The percent of change. Well, first things first 7:45 has 2 different units, wich are minutes and seconds, I suppose. Same goes for 5:51.
So let's put everything in seconds. multiply both the 7 and 5 for 60(for every minute has 60 seconds.)
That means:
7*60= 420+45 = 465.
5*60=300+51=351.
Now, let's do the math itself:
465 -> 100%
351 -> x%
Is equal to about 75,5%
How much did it decrease then?
(75,5-100)%= 24,5%, approximately