Suma dintre un număr şi 15 este 28. Care este numărul considerat?
1 answer:
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Answer:
<u><em>(-1,1)</em></u>
Step-by-step explanation:
We can solve this by either graphing and finding ther point the lines intersect, or mathematically, I'll do both.
<u>Graphing:</u>
<u>Mathematically:</u>
−2x + 4y = 6
y = 2x + 3
See the attached graph. The lines intersect at (-1,1)
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I'll rearrange the first equation (to make it easier for me):
−2x + 4y = 6
4y = 2x + 6
y = (1/2)x + 1.5
Now lets substitute the second equation into the first so that we can eliminate y:
y = 2x + 3
[(1/2)x + 1.5] = 2x + 3
- (3/2)x = (3/2)
x = -1
If x = -1:
y = 2(-1) + 3
y = 1
The solution is x = -1 and y = 1, or (-1,1)
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Both approaches give us (-1,1), the solution to the system of equations. It is the only point that satisfies both equations.
