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

you have y=mx+b
5 = (2)(-1) + b, so b = 7, so the equation would be y=2x+7

Answer 2

okay and what's next

Answer 3

now in standard form, you can see which one will convert to y= 2x +7 by isolating the y, you know that the y-int =7 and not 11, so it must be between a or b

Answer 4

is it A?

Answer 5

if it was A, then plugging (-1, 5) into choice A should give a true statement

–2x – y = –7

–2(-1) – (5) = –7 ... plug in x = -1 and y = 5

2 - 5 = -7

-3 = -7

but the last equation is false, so –2x – y = –7 is false when x = -1 and y = 5

So (-1, 5) is NOT a solution to –2x – y = –7

Answer 6

so it is B

Answer 7

lets try a to see what we get

-2x -y = -7
-y = 2x -7
--- -- --
-1 -1 -1

= y = -2x +7 what do you think

Answer 8

the answer is B, right?

Answer 9

let's try B

2x – y = –7

2(-1) – (5) = –7

-2 - 5 = -7

-7 = -7

that's true, so (-1,5) is indeed a solution to 2x - y = -7

Answer 10

to confirm the slope for B is 2, simply solve for y and get it into y = mx+b form

Answer 11

thanks guys so the answer is 2x-y= -7

Answer 12

yep

Answer 13

correct