Question

give the solution set of system
6x + 9y = 7
3x - 6y +14 = 0


Please answer clearly and explain the solution clearly and easy to understand. Thanks!
(guaranteed medal for a good answer)

Answer 1

-4/3, 5/3

Answer 2

6x + 9y = 7 6x + 9y = 7 6x+9y=7
3x - 6y +14 = 0 3x - 6y =-14 (*-2)---> -6x+12y=28(add both eq)

21y=35
y=35/21=5/3 replace y in the 1st eq 6x+9*35/21=7
6x=7-15
x=-8/6=-4/3
so the solution is (-4/3;5/3)

Answer 3

Rearrange each equation to get x (or y) on its own:
\[6x + 9y = 7 => 6x = 7 - 9y => x = \frac{7 - 9y}{6}\]\[3x - 6y + 14 = 0 => 3x = 6y - 14 => x = \frac{6y - 14}{3}\]
Now we have x in two different forms, which are equal. So set them to be equal!
\[\frac{7-9y}{6}=\frac{6y-14}{3}\]\[3(7-9y) = 6(6y-14)\]\[21-27y=36y-84\]\[y=\frac{5}{3}\]
Put that y in one of the first equations to find x:
\[x=\frac{7-9y}{6}\]\[x=\frac{7-9(5/3)}{6}\]\[x=-\frac{4}{3}\]

Answer 4

thanks
i forgot the negative sign, now i know what is wrong with my solution

Answer 5

uw

Answer 6

i'll really be careful know with signs

Answer 7

my first answer recently is always y= 7

Answer 8

cause i forgot the - sign

Answer 9

^_^

Answer 10

I forget them too :/