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solmaris [256]
3 years ago
6

If (a+b)(a-b)=21,a+b=7 and a-b=3 what Is the value of a

Mathematics
1 answer:
topjm [15]3 years ago
8 0

9514 1404 393

Answer:

  5

Step-by-step explanation:

Add the latter two equations and you get ...

  (a +b) +(a -b) = (7) +(3)

  2a = 10 . . . . . . . . . . . . . . . simplify

  a = 5 . . . . . . . divide by 2

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Give me the best answer
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79,86,88,88,92,98,100,106,115,136

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because the outliers are >  115  (up to 136)
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7 0
3 years ago
Rewrite each equation in slope-intercept form, if necessary. Then determine whether the lines are parallel. Explain,
Oksana_A [137]
Answer:
d

Step-by-step explanation:

Slope intercept form: y = mx + b

y = -x + 7
x + y = 21

x + y = 21
-x -x
y = -x + 21


y = -x + 7
y = -x + 21

Parallel lines have the same slope. Here, our slope is -1

Therefore, our final answer is d.


Hope this helps!
8 0
2 years ago
Solve this system of equations. y = 5x +20 and y = -2x -8
Thepotemich [5.8K]

Answer:

y = 0

x = -4

( x, y ) = ( -4 , 0 )

Step-by-step explanation:

y = 5x + 20

y = -2x - 8

Substitute

5x + 20 = -2x - 8

Add 8 on both sides

5x + 20 + 8 = -2x - 8 + 8

5x + 28 = -2x

Subtract 5x on both sides

5x - 5x + 28 = -2x - 5x

28 = -7x

Divide by -7 on both sides

28/-7 = -7x/-7

-4 = x

Now that you have x, you can substitute it in one of the equations that was given to find the value of y.

y = 5x + 20

y = 5(-4) + 20

y = -20 + 20

y = 0

Or....

y = -2x - 8

y = -2(-4) - 8

y = 8 - 8

y = 0

They will both be 0 no matter what

Point form = ( -4, 0 )

Hope this helped

3 0
3 years ago
A sphere with a circumference of 42" has the volume of what
marissa [1.9K]
<span>263.894 is the answer</span>
8 0
3 years ago
Burak runs a Turkish restaurant. One day, he records that he sells two popular dishes, sasuka and pide, in the ratio 3:5. If Bur
Natasha2012 [34]

Step-by-step explanation:

<h2>sasuka:pire</h2><h3> 3:5</h3><h3>3/8:5/8=3/8×24×8/5 </h3>

= 14.4

7 0
3 years ago
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