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S_A_V [24]
3 years ago
12

Find 51* 49 USING MENTAL MATH'

Mathematics
2 answers:
Nesterboy [21]3 years ago
7 0
I used mental math and it took a long time, but I got the answer of 2,499.
goldfiish [28.3K]3 years ago
7 0

Answer:

The value of given expression is 2499.

Step-by-step explanation:

The given expression is

51\cdot 49

This expression can be written as

(50+1)\cdot (50-1)

Using the property of algebraic expression we get

(50+1)\cdot (50-1)=(50)^2-1^2          [\because (a-b)(a+b)=a^2-b^2]

(50+1)\cdot (50-1)=2500-1

(50+1)\cdot (50-1)=2499

Therefore the value of given expression is 2499.

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It is not 90 degrees it is 87
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In which square is 25% not shaded
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Square D because 2/8 are not shaded. 2/8=1/4 and 1/4=25%
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Read 2 more answers
Can someone plz do the dimensional analysis for 32ft/6.45 sec to meters/min? Thank You!
Rzqust [24]

Answer:

About 90.73 meters/min.

Step-by-step explanation:

Dimensional analysis is done by multiplying the wanted unit over the current unit in equal measure, or the other way around.

First, we will convert feet to meters, using that 1 ft = .4048 m.

32ft/6.45sec * .3048m/1ft = 32/6.45sec * .3048m = 9.7536m/6.45 sec.

Second, we convert seconds to minutes, using that 60 sec = 1 min.

9.7536m/6.45sec * 60sec/1min = 9.7536*60m/6.45min ≈ 90.7311627m/min.

5 0
3 years ago
What is (9^4)^2?<br> And what is (6^1)^0?
Alexandra [31]

Answer:

hhhhgvguhvibjhvgyvv

Step-by-step explanation:

bhufyhg88

8 0
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.

7) f:\Re\geq 0 \rightarrow  \Re\geq0, f(x) =x^{4}

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

7 0
3 years ago
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