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math help ! solving elimination in non standard form!!?
9x - 3y = 63
7x - 3y = 45
7 Answers
- ?Lv 78 years ago
9x - 3y = 63
7x - 3y = 45.........Multiply by - 1
9x - 3y = 63
-7x + 3y = -45
*****************ADD
2x = 18
x = 9
9(9) - 3y = 63
81 - 3y = 63
-81........- 81
- 3y = - 18
y = 6
( 9 , 6 ) ......................ANSWER
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- Anonymous8 years ago
9x-3y=63
7x-3y=45
9x-3y=63
-7x=3y=-45
(-3y and +3y gets canceled and the rest we solve it)
it becomes:-
2x= 18
then,
x=18/2=9
therfore,
x=9
to find y(substitute the value of x in any one eq.)
7x-3y=45
7(9)-3y=45
63-3y=45
-3y=-18
y=6
therefore the value of:
x=9 , y=6
- MoonLv 78 years ago
9x - 3y = 63 ........eq1
7x - 3y = 45 .........eq2
-----------------------------
2x = 18 ..............eq1 - eq2
x = 9 ..................................... x solved
9x - 3y = 63 ........eq1
81 - 3y = 63
-3y = 63 - 81 = -18
y = 6 ....................................... y solved
check:
7x - 3y = 45 .........eq2
7*9 - 3*6 = 45
63 - 18 = 45 ........................ true!!!
Our answer is:
(x,y) = (9, 6)
.......
- ComoLv 78 years ago
9x - 3y = 63
-7x + 3y = - 45______ADD
2x = 18
x = 9
63 - 3y = 45
18 = 3y
y = 6
x = 9 , y = 6
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- 8 years ago
-1 (9x-3y=63
7x-3y=45
-9x+3y=-63
7x-3y=45
--------------
-2x=-18
x=9 if x=9 y=6
- notthejakeLv 78 years ago
9x - 3y = 63
7x - 3y = 45
------------------ (subtract)
2x = 18
x = 9
and if x =9, then 9(9) - 3y = 63
81 - 63 = 3y
18 = 3y
y = 6
(9 , 6) = (x , y)
check in the other equation:
7(9) - 3(6) = 63 - 18 = 45 checks
- veneziaLv 44 years ago
the 1st ingredient to do is to get the equations into familiar variety: 6x -6y = 6 -4x + 8y = 4 divide out the 6 from the 1st equation and divide the 2nd equation through four. you will then have: x - y = a million -x + 2y = a million upload the two equations. the x's cancel out and you have: 2y - y = 2 y = 2 exchange y=2 into the 1st equation to get x - 2 = a million x = 3