Question

how to solve for this polynomial
4x+5y+9y-2y=13x+13y

Answer 1

get all the x's on one side, and then all the y's on the other, then factor out the y's and x's. then divide through to solve for either y or x

Answer 2

can you show how to do it?

Answer 3

get anything multiplied by an x on one side, and anything multiplied by a y on the other, then type what you get

Answer 4

so for instance, to move the 4x over to the right, i would subtract 4x from both sides

Answer 5

i dnt understand

Answer 6

so at the moment you have "some equation = some other equation"

the equals sign means that both sides have the same value. so adding something to one side means you have to add to the other to keep the same value

Answer 7

you need to move the 4x across. so subtract 4x from the right, and from the left

Answer 8

can you show step by step I am really confused

Answer 9

4x+ 5x + 9y - 2y = 13x + 13y is your equation

Answer 10

k

Answer 11

so if i subtract 4x from both sides i get
5x + 9y - 2y = 13x + 13y - 4x

Answer 12

i have to do it to both sides at the same time, so it stays balanced.

Answer 13

do you see why?

Answer 14

does this make sense so far

Answer 15

yes so what do i do next?

Answer 16

so now you need to get rid off the 13y on the right hand side. Do that and type wwhat you get

Answer 17

13y-5x+9y-2y=13x-4x

Answer 18

yeah awesome! i think you misstyped the 5y for 5x but thats great

Answer 19

so we have

13y-5y+9y-2y=13x-4x

Answer 20

now we use the sneaky trick of factoring in order to clean up all those untidy y's

Answer 21

y(13-5+9-2) = 13x - 4x

Answer 22

can you see what ive done? ive "pulled" the y out from each bit in the equation.

Answer 23

and so y mutiplies by the whole thing at once, instead of each bit in turn

Answer 24

get it?

Answer 25

so what do i do next?

Answer 26

okay now you do the same with the x side, and type what you get

Answer 27

y(13-5+9-2)=x(13-4)

Answer 28

yeah awesome which is y15 = x9

Answer 29

are you solving this for y or for x?

Answer 30

both

Answer 31

you have to chose to solve it for y in terms of x, or x in terms of y

Answer 32

either way if its y you want, divide through by 15, if its x then divide by 9

Answer 33

divide what by 15 or 9

Answer 34

both sides, remember whatever you do to one side you have to do to the other

Answer 35

so to get y, if we divide by 15 we get

y = 9x/15

Answer 36

0.6

Answer 37

well we dont know what x is, so yeah it could be y = 0.6x

but normally we like to leave it with whole numbers. y = 9x/15 it depends what your teacher wants you to do

Answer 38

for x I got 0.6

Answer 39

oh? whats y?

Answer 40

y=0.6

Answer 41

ahh did they give you that at the start of the question?

Answer 42

x=1.6

Answer 43

no gave us nothing for the question

Answer 44

then how do you know y is 0.6 and not say... 10?

Answer 45

or 100, or 123123, or 2341234.2134 or anything

Answer 46

i'm confused

Answer 47

well you have

\[y = \frac{9x}{15}\]

Answer 48

which is \[y = 0.6x\]

Answer 49

if you decide to divide 9 by 15

Answer 50

okay

Answer 51

so it would be 1.6

Answer 52

no. my point is you cant tell what x or y are.

Answer 53

they can be any number. for instance what if x = 1? then we have

y = 0.6(1) so y = 0.6

Answer 54

but what if x = 2?
y = 0.6(2) so y now = 1.2

Answer 55

so there is no definite answer to find x or y

Answer 56

no you need more information

Answer 57

how about this questions how many terms are in this equation. (x+y)(xsquare+2xy+ysquare). Then work out the multiplication and combine like terms

Answer 58

now there are times when you might have an equation like say

y = 3x + 2

and the question would be "x is the distance, and y is the hight. Find out how high Hailey jumps when she travels 5 meters"

then you could put "5" for x:
y = 3(5) + 2 y = 17

Answer 59

can you help me with the question above?