Question

solve polynomios subtract please 7.8x-3.4y+z -9.2x+4.8y-2.1z

Answer 1

Is it (i) (7.8x-3.4y+z) - (-9.2x+4.8y-2.1z)
or (ii) (-9.2x+4.8y-2.1z) - (7.8x-3.4y+z ) ?

Answer 2

it's (7.8x-3.4y+z) - (-9.2x+4.8y-2.1z)

Answer 3

(7.8x-3.4y+z) - (-9.2x+4.8y-2.1z)

= (7.8x-3.4y+z) - (-9.2x) - (+4.8y) - (-2.1z)

Can you simplify the brackets first?

Answer 4

there is no brackets

Answer 5

Oh.. I mean those (..... ) - (....)
For example:
- (+4.8y) = -4.8y

Answer 6

16.38x - 7.14y + 2.1z
-9.2x + 4.8y - 2.1z

... correct me if I'm wrong

Answer 7

(7.8x-3.4y+z) - (-9.2x+4.8y-2.1z)
= (7.8x-3.4y+z) - (-9.2x) -(+4.8y) -(-2.1z)
= (7.8x-3.4y+z) + 9.2x - 4.8y + 2.1z
= ...

- (-9.2x) = (-1) (-9.2x) Negative times negative is positive, so you get
= 9.2x
Same for -(-2.1z)

-(+4.8y) = (-1)(+4.8y) Negative times positive is negative, so you get
= -4.8y

Clear?

Answer 8

clear

Answer 9

Now, group the like terms together, do the addition/subtraction for 7.8x-3.4y+z + 9.2x - 4.8y + 2.1z

Answer 10

17.0x-8.2y+3.1z

...again correct me if I'm wrong

Answer 11

It's right :)

Answer 12

another?

Answer 13

The volume (v) of a sphere varies directly as the cube of its diameter (d). Write this statement in algebraic language, using an equation with the variables c, v, and d.

Answer 14

Start a new post for a new question!

Answer 15

thank you fro you time:)