Question

Add the following: (-8x2 – 2x + 4) + (x2 – 9x + 7)

Answer 1

add the like terms

Answer 2

-8x^2 - 2x + 4 + x^2 - 9x + 7= -7x^4 + 11x^2 + 11

Answer 3

Do not add the exponents.

Answer 4

okay so it would be x^2 and x right?

Answer 5

yes

Answer 6

but -11x

Answer 7

Add the following: (8.1x2 – 5.9x – 7.1) + (-9.8x2 – 8.1x – 4.8)

Answer 8

Aaron, do you understand what you are doing?
(-8x2 – 2x + 4) + (x2 – 9x + 7). when you add those two expressions, you add the like terms. lets call x2 as oranges. lets call x apples

so what that equation tells you is that you have -8 oranges and -2 apples and 4 dollars.
you add 1 orange subtract 9 apples and add 7 dollars. what do you have left?

Answer 9

x and x^2 are basically symbols. they can be used to represent anything.

Answer 10

in more abstract terms, you are adding -8 of "x-squared" , -2 of "x" and 4 to 1 of "x squared" -9 of "x" and 7

Answer 11

right which gives me -7x^2 - 11x + 11

Answer 12

yup! very good. do the rest similarly

Answer 13

just visualize x squared as oranges and x as apples

Answer 14

okay stay and tell me if I do it right please

Answer 15

take 3 oranges and add 4 apples and get 45 dollars from your dad.

that is : 3x^2 + 4x + 45 and so on.

Answer 16

note that you can't mix apples and oranges.

Answer 17

similarly you cannot mix x and x^2 and add them up

Answer 18

8.1x^2 - 5.9x - 7.1 + -9.8x^2 - 8.1x - 4.8 = -1.7x^2 + -14x + -11.9

Answer 19

or did I do that wrong

Answer 20

yes, that is correct. While it is semantically true that adding a negative number can be represented as + - 14x, we prefer to simply write it as -14x implying that we are subtracting 14x

Answer 21

okay

Answer 22

adding a negative number is nothing but subtracting it.

Answer 23

so it will look like this -1.7x^2 - 14x - 11.9 right?

Answer 24

yup. very good!

Answer 25

Thank you and gave you a medal also thanks