Question

PLEASE HELP WILL GIVE MEDAL!!!!!!!!!!!!!!!!!!!!!

Answer 1

the points (4,-2) and (-2,8) lie on the line Ax-2 By=28. what is the value of A?

Answer 2

since the given points lie on the line,
they must satisfy the line

Answer 3

plug them get two equations

Answer 4

how?

Answer 5

Ax-2 By=28

plugin the first point : (4, -2)

A(4) - 2B(-2) = 28
4A + 4B = 28
A + B = 7 ---------------------(1)

Answer 6

similarly plugin the other point, and see if u can get another equation ?

Answer 7

okay...
2x+16B=28?

Answer 8

try again

Answer 9

wait i did it wrong, its 2A+16B=28

Answer 10

correct?

Answer 11

Ax-2 By=28

plugin the first point : (-2, 8)

A(-2) -2B(8) = 28

-2A -16B = 28

A + 8B = -14 --------------------(2)

Answer 12

^^

Answer 13

but the point was(2, -8)

Answer 14

@shubhamsrg can u help me

Answer 15

ur back!

Answer 16

@ganeshie8 this wasn't the first point: "plugin the first point : (-2, 8)"

Answer 17

ahh typo, scratch that.. see if below looks okay :

Ax-2 By=28

plugin the SECOND point : (-2, 8)

A(-2) -2B(8) = 28

-2A -16B = 28

A + 8B = -14 --------------------(2)

Answer 18

your two equations are :
A + B = 7 ---------------------(1)
A + 8B = -14 --------------------(2)

Answer 19

the second point was (2,-8)

Answer 20

then work the second equation again

Answer 21

but the original question says :
```
the points (4,-2) and (-2,8) lie on the line Ax-2 By=28. what is the value of A?
```

Answer 22

was there a typo ?

Answer 23

yes im stupid, im so sorry, i meant to say (2,-8)

Answer 24

alright. so 2A+16B=28

Answer 25

Looks good !

Answer 26

A+8B=14

Answer 27

Now i get it!!

Answer 28

so your equations are :
A + B = 7 ---------------------(1)
A+8B=14 ---------------------(2)

Answer 29

yes

Answer 30

eliminate B since you want the value of A

Answer 31

may be solve for B from first equation,
then substitute it in 2nd equation

Answer 32

so you would multiply 8(A+B=7)

Answer 33

negative 8 actually

Answer 34

okay then subtract ..... A=6!

Answer 35

not 6 factorial, just 6

Answer 36

thanks @ganeshie8

Answer 37

A = 6 is \(\large \color{red}{\checkmark }\)

http://www.wolframalpha.com/input/?i=A+%2B+B+%3D+7%2C+A%2B8B%3D14+

Answer 38

really appreciated ur help

Answer 39

u wlc :)