Question

standard form help? y = -4/9x - 9.7

Answer 1

standard form?

Answer 2

here's the full question


it gives me 4x = 9y = -23, and then tells me to write the equation of a line that would be parallel to that line in standard form with points (12, -15), so i came up with the slope-intercept form of a line that's parallel to that:

y = mx + b

y = -15
x = 12

-15 = m12 + b

the slope is -4/9 so


-15 = (-4/9)12 + b

solve for b

b = 9.7

so it'd be y = -4/9x + 9.7

right?

how do i write this in standard form?

Answer 3

http://www.mathsisfun.com/algebra/standard-form.html

Answer 4

Set it equal to zero.

Answer 5

oh wait b is wrong, -4/-9 = +.4.


.4 x 12 = 4.8

4.8 + b = -15

b = -19.8?

Answer 6

DId you read the link I posted above?

Answer 7

oh wait b is wrong, -4/-9 = +.4.


.4 x 12 = 4.8

4.8 + b = -15

b = -19.8?

Answer 8

i need to make sure my slope-intercept form is right first.

y = -4/9x -19.8?

Answer 9

Do you know how to check it?

Answer 10

-15 = -4/9(12) - 19.8

-4/9 = .4

.4 x 12 = 4.8

-15 = 4.8 - 19.8

Answer 11

yep

Answer 12

to write it in standard form

y = -4/9x - 19.8

multiply each side by -9

-9y = -4x - (-178.2)

add 4x to each side

4x - 9y = 178.2

subtract 178.2 from each side

4x - 9y - 178.2 = 0

but my book says the answer is 4x - 9y - 183 = 0. where does 183 come from? closest i can get is 178.2

Answer 13

go back and make sure b is correct or your answer key could be incorrect

Answer 14

b has to be correct because -4/-9 = 0.4 repeating

Answer 15

Well everything looks good to me.

Answer 16

thank you!