1) -3(5x+2y=-3)⇒ -15x-6y=9
⇒ -9x=27
2(3x+3y=9)⇒ 6x+6y=18
2) -9x/-9=27/-9 ⇒ x=-3
3) 3(-3)+3y=9⇒ -9+9+3y=9+9⇒ 3y/3=18/3⇒ y=6
Answer: (-3,6)
Reasoning:
Step 1) In order to eliminate, first I had to multiple the first equation by -3 and the second by 2 so that when combining the equations y would cancel each other out so that I could solve for x. <em>Note: There are many combinations as to how you could multiple the equations so that either the x or y would cancel out.
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Step 2) Once y is eliminated, solve for x.
Step 3) Now plug x back into one of the original equations and solve for y. <em>Note: Plug x back into one of the original equations, not the equations that were changed by multiplication,</em>
Answer:
18432 km/h
Step-by-step explanation:
It is given that a sound wave travels through iron at a rate of 5120 m/s.
We know that
1 km = 1000 m
1 hour = 60 minutes
1 minutes = 60 second
Using these conversions we get
1 m = 0.001 km
1 hour = 3600 second


Therefore, the sound wave travels through iron at a rate of 18432 km/h.
Answer:
5mph
Step-by-step explanation:
Given that two cars are 40 miles apart at the beginning.
They started at the same time with speeds 48 mph and 56 mph respectively
Since both cars are travelling in the same direction,
Relative velocity = Speed of the behind car-Speed of the first car
=56-48 =8mph
To catch the I car, the second car has to travel a distance of 40 miles extra in the same time as the I car
i.e. speed to be made up by the second car = 40 miles
Relative velocity per hour = 8mph
Hence time taken to catch up = 
I hope it can help you hehehe