Question

Write the equation of the line that passes through (–1, 5) with a slope of 2 in standard form.

–2x – y = –7

2x – y = –7

2x – y = 11

–2x + y = –11

Answer 1

this one too @jim_thompson5910 please

Answer 2

y - y1 = m(x - x1)
slope(m) = 2
(-1,5) x1 = -1 and y1 = 5

now lets sub our stuff in...
y - 5 = 2(x - (-1)
y - 5 = 2(x + 1)
y - 5 = 2x + 2
y = 2x + 2 + 5
y = 2x + 7

standard form :
y = 2x + 7
-2x + y = 7 (multiply by -1)
2x - y = -7

Answer 3

any questions ?

Answer 4

The reason why I multiplied by -1 is because we do not want x being negative

Answer 5

ok @texaschic101 yea i see that but i dont undestand why

Answer 6

Ax + By + C is the standard formula.
" A" is not supposed to be negative....I am not sure if that is a rule or not, but I try not to let it be negative.

Answer 7

Write the equation of the line that passes through (1, 3) and (4, 4) in standard form.

3x – 3y = –8

x – 3y = –9

x – 3y = –8

3x + y = 9

Answer 8

can you help me with this one too @texaschic101

Answer 9

for this one we need to find the slope by using the slope formula.
slope(m) = (y2 - y1) / (x2 - x1)
(1,3) x1 = 1 and y1 = 3
(4,4) x2 = 4 and y2 = 4
now lets sub..
m = (4 - 3) / (4 - 1)
m = 1/3

now we use this one :
y - y1 = m(x - x1) and we can use either of the points
I will use (1,3) and slope 1

y - 3 = 1/3(x - 1)
y - 3 = 1/3x - 1/3
y = 1/3x - 1/3 + 3
y = 1/3x - 1/3 + 9/3
y = 1/3x + 8/3

standard form :
y = 1/3x + 8/3 (multiply by 3 to get rid of fractions)
3y = x + 8
-x + 3y = 8 (multiply by -1)
x - 3y = -8

Answer 10

wait is this called point-slope formula?

Answer 11

I used the point slope formula : y - y1 = m(x - x1) and then turned it into standard form

Answer 12

I used the point slope because we had a point and we had the slope