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Archy [21]
3 years ago
14

Evaluate 5x2−9 when x=−2

Mathematics
1 answer:
Elena-2011 [213]3 years ago
3 0

answer: 11

explanation: just plug in -2 for x. the new problem becomes 5(-2)^2 - 9. Negative two squared is 4. 5 times 4 is 20. 20 minus 9 is 11.

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the length of a rectangular garden is 3 m greater than the width. The area of the garden is 70m squared. find the dimensions of
Lerok [7]
A = l x w

so you know that the length is 3m longer than the width, so you could use a formula to represent that

w = l + 3

you then substitute the second equation into the first to solve for l

70 = l x (l +3)
70 = l^2 + 3l

you could then rearrange the formula and solve for l using the quadratic formula 

0 = l^2 + 3l - 70

l = -3 +- (square root (3)^2 - 4(1)(70)) / 2(1)
l = -3 +- (square root 9 + 280) / 2
l = -3 +- (square root 289) / 2
l = -3 +- 17 / 2

then you solve for the two seperate roots

l = -3 + 17 /2
l = 14 / 2
l = 7

or 

l = -3 - 17 / 2
l = -20 / 2
l = -10

since a length cannot be negative, this root is not viable. therefore l = 7

to solve for w you would use

w = l + 3
w = 7 + 3
w = 10 

hope this helps! if you did not understand a step or concept please let me know!
4 0
3 years ago
a cell phone company charges a monthly fee plus a 0.35 for text messages sent they charge 25.00 monthly fee and your bill is 58.
riadik2000 [5.3K]
Hey,

So first we are told that they charg a fixed fee of 25:00 right?That means even if you didn’t send any text messages you still have to pay 25:00.

So first we have to subtract that 25:00 form 58.25 right?This means the rest of the bill is for text messages OK?
So he spent 33.25(this is the answer to the subtraction) on the text messages right?
And for every text he sent he was charged 0.35 right? So we have to divide 33.25 by 0.35 right?
And that gets us 95.

Now we can double check the answer by multiplieng 95 by 0.35 and adding 25.

So th answer is 95

Hope this helps !!
6 0
3 years ago
Which one answers this equation
alexgriva [62]
/ (divided by) I think it is right
3 0
2 years ago
Mr. Drew wants to build a square sandbox with an area of 289 square feet. What is the total length of wood Mr. Drew needs to mak
alisha [4.7K]

Answer:

  68 feet

Step-by-step explanation:

A square with area 289 ft² has sides √289 = 17 ft long. There are 4 of them so the perimeter is 4×17 ft = 68 feet.

Mr. Drew needs 68 feet of wood for the sides of the sandbox.

5 0
3 years ago
I need help I don’t get this
Anton [14]
The answer would be A, 21.  This is because 16 is 2/3 of 24 and 14 is 2/3 of 21
3 0
3 years ago
Read 2 more answers
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