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2 years ago

Use substitution to solve the system of equations :

Mathematics

1 answer:

mote1985 [20]2 years ago

3 0

Answer:

x=1

y=-4

Step-by-step explanation:

4x+y=0 -> y= -4x

2(-4x)+x=-7

-8x+ x=-7

-7x=-7

x=-7/-7=1

y=-4 . 1 = -4

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Find the critical value t a/2 needed to construct a confidence interval of the given level with the given sample size. level 95%

stepan [7]

Α = 1- (95/100) = 1-0.95 = 0.05

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From t-tables, with cumulative probability pf 0.975 and df of 10,
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2 years ago

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Mrrafil [7]

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Step-by-step explanation:

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3 years ago

Complete the description of the translation

Anit [1.1K]

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3 years ago

For each of the following functions, determine if they are injective. Also determine if theyare surjective. Also determine if th

timurjin [86]

Answer:

Check below

Step-by-step explanation:

1. Definition for intervals

$(a,b)=\left \{ x\in\Re : a$

2. Functions

1) $\Re \rightarrow \Re \\ f(x)=x$

Let's perform graph tests.

That's an one to one, injective function. Look how any horizontal line touches that only once. Also, It's a surjective and a bijective one.

2) $\Re\geq0\rightarrow\Re , f(x)=x+1\\$

Injective, surjective and bijective.

Injective: a horizontal line crosses the graph in one point.

3) $f:\Re\geq 0\rightarrow\Re, f(x) = cos(x)$

The cosine function is not injective, bijective nor surjective.

4) $f:\Re\rightarrow\Re \:f(x)=ex$

Since e, is euler number it's a constant. It's also injective, surjective and bijective.

5) Quite unclear format

$6) \:f:\Re\rightarrow(0,\infty), f(x) =ex$

Despite the Restriction for the CoDomain, the function remains injective, surjective and therefore bijective.

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Not injective nor surjective therefore not bijective too.

$8).f:\{-1,2,-3\}}\rightarrow \{1,4,9\}, f(x) =x^{2}$

$f(-1)=1, f(2)=4, f(-3)=9$

Injective (one to one), Surjective, and Bijective.

$10) f:\Re\geq 0\rightarrow [-1,1], f(x)= cos(x)\\-1=cos(x) \therefore x=\pi,3\pi,5\pi,etc.$

Surjective.

$11.f:R\geq 0[-1,1], f(x) = 0\\$

Surjective

12.f: US Citizens→Z, f(x) = the SSN of x.

General function

13.f: US Zip Codes→US States, f(x) = The state that x belongs to.

Surjective

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2 years ago

making 10 pounds of Apple Jam requires five pounds of Apple how many pounds of Apple are needed to make eight pounds of apple ja

allochka39001 [22]

10lb. of jam needs 5lb. apple, or 2lb. of jam needs 1lb. apple.
Now we want 8lb. of jam.
Set up a proportion:
2/1=8/x
Solve for x by cross-multiplying.
2x=8
x=4 lb. of apple

5 0

3 years ago