Mathematics, 26.01.2020 03:31 alexdonatalex1314

Find the value of the polynomial 3xy+7x^2−3x^2y+3y^2x−2x^2−2xy+4x^2y −2y^2x, when x=1 and y=−2

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Answer from: bubs9789

First Method:

Substitute the given values in for

and

.Solve.

This isn't the only method, but it seems the least likely to result in an incorrect answer.

If x=1 and y=-2 , find the solution to:

3xy+7x^2-3x^2y+3y^2x-2x^2-2xy+4x^2y-2y^2x

Substitute

for

and

for

$3xy+7x^2-3x^2y+3y^2x-2x^2-2xy+4x^2y-2y^2x\\3(1)(-2)+7(1)^2-3(1)^2(-2)+3(-2)^2(1)-2(1)^2-2(1)(-2)+4(1)^2(-2)-2(-2)^2(1)$

Wow. That's a lot. Let's try simplifying things. I'd start by multiplying all our

's because any number multiplied by

is that very same number, so we can easily reduce the length of our equation without much worry for messing up our math in the process.

3(-2)+7-3(-2)+3(-2)^2-2-2(-2)+4(-2)-2(-2)^2

It still looks like torture trying to figure out this equation, but let's take it in chunks instead of all at once.

3(-2)+7-3(-2)+3(-2)^2-2-2(-2)+4(-2)-2(-2)^2

First, I'm going to deal with all the exponents, and turn them into integers.

3(-2)+7-3(-2)+3(4)-2-2(-2)+4(-2)-2(4)

Notice that things are starting to look less complicated. We are taking our math in chunks. This will make it less likely for us to mess up, although it is more time consuming.Now, let's do multiplication. Any number within a parentheses is going to be multiplied by the number next to it. Remember that this only applies when there is no sign between them. I'm going to go one at a time.

$3(-2)+7-3(-2)+3(4)-2-2(-2)+4(-2)-2(4)\\-6+7-3(-2)+3(4)-2-2(-2)+4(-2)-2(4)\\-6+7+6+3(4)-2-2(-2)+4(-2)-2(4)\\-6+7+6+12-2-2(-2)+4(-2)-2(4)\\-6+7+6+12-2+4+4(-2)-2(4)\\-6+7+6+12-2+4-8-2(4)\\-6+7+6+12-2+4-8-8\\$

This is a lot of steps, but hopefully it doesn't looks as bad after seeing that I just did multiplication over and over. I'll go over another method after this that may make things less complicated.Now, we add these together. It doesn't matter what order you do this in.

$-6+7+6+12-2+4-8-8\\7+4+6+12-6-2-8-8\\11+18-8-16\\29-24\\5$

Our final answer is .

Here's another method:

If x=1 and y=-2 , find the solution to:

3xy+7x^2-3x^2y+3y^2x-2x^2-2xy+4x^2y-2y^2x

Because we know that any number multiplied by

will be that same number, let's just substitute in

for now.

$3xy+7x^2-3x^2y+3y^2x-2x^2-2xy+4x^2y-2y^2x\\3(1)y+7(1)^2-3(1)^2y+3y^2(1)-2(1)^2-2(1)y+4(1)^2y-2y^2(1)\\$

Now, just like before, we can multiply

without doing complicated math. Just basically get rid of it even when it's squared because 1^2=1*1=1

$3(1)y+7(1)^2-3(1)^2y+3y^2(1)-2(1)^2-2(1)y+4(1)^2y-2y^2(1)\\3y+7-3y+3y^2-2-2y+4y-2y^2\\3y^2-2y^2+3y-3y-2y+4y+5\\y^2+2y+5$

Looks a LOT less complicated. Substitute

in for

and get your final answer.

$y^2+2y+5\\(-2)^2+2(-2)+5\\4-4+5\\5$

Answer from: Quest

the final amount you will pay is $68.04.

the tip is determined by the pre-tax amount, so we calculate the tip based on the original bill, not after we've added sales tax.

to find the tip:

we can divide 54.00 by 100 to get 1% of 54. then we multiply that by 18.

54 / 100 = .54

.54 x 18 = 9.72

tip = 9.72$

to find the tax:

we can divide 54.00 by 100 to get 1% of 54. then we can multiply that by 8 to get 8%.

54 / 100 = .54

.54 x 8 = 4.32

tax= 4.32

now we can add the tip and tax to the bill to get our total.

54 + 9.72 + 4.32 = 68.04

total: $68.04

step-by-step explanation:

Answer from: Quest

answer: the answer is fre sha voca do

step-by-step explanation:

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Find the value of the polynomial 3xy+7x^2−3x^2y+3y^2x−2x^2−2xy+4x^2y −2y^2x, when x=1 and y=−2...

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