A few days ago
Anonymous

Algebra homework help?

you have to solve the equation for y. then find the value of y for the given value of x. there are two answers.

these were the only ones i got stuck on. thanks for the help!

xy-3x=40; x=5

7x-xy= -18; x= -4

3xy-28=16x; x=4

9y+6xy=30; x= -6

4 – 2xy=15; x= -1

4x+7y+5xy=0; x=1

Top 3 Answers
A few days ago
Fi B

Favorite Answer

First create a formula for y. Enclose number sets in brackets to help you keep track of what you’re doing.

xy-3x =40

xy=40+3x

y=(40+3x)/x

Then substitute x=5

y=(40+[3×5])/5

y=(40+15)/5

y=55/5

y=11

Double check original formula

xy-3x=40

5y-(3×5)=40

5y-15=40

5y=40+15

5y=55

y=55/5

y=11

Now you know you’ve got it right.

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A few days ago
Eric212
xy-3x=40; x=5

(5)y-3(5)=40

5y-15=40

5y=40+15

5y=55

y=11

7x-xy=-18 ; x=-4

7(-4)-(-4)y=-18

-28+16y=-18

16y=-18+28

16y=10

y=10/16=5/8

the next several are much the same… try them yourself

4x+7y+5xy=0; x=1

4(1)+7y+5(1)y=0

4+7y+5y=0

4+12y=0

12y=-4

y=-4/12=-1/3

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A few days ago
Anonymous
first you have to isolate the y value. get the y on one side of the equals sign and everything else on the other. that’s how you solve for y.

then plug in your x value and solve.

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