Solve by using the elimination method.
11x + 12y = 144
x + 2y = 14
A (29, -36)
B (20, -1)
C (-17, -3)
D (12, 1)
E (-2, -4)
F (-3, 38)
2007-07-07 14:53:26 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
D.
Quick way by elimination. 1 is the only number less than 14 which multiplies by 2 would still be a positive number.
2007-07-07 15:00:53 · answer #1 · answered by Marvinator 7 · 0⤊ 0⤋
Stack the equations.
11x + 12y = 144
x + 2y = 14
You should eliminate either x or y.
Multiply the entire line by the opposite (negative) value equivalent of one of the "larger" letters.
11x + 12y = 144
-11( x + 2y = 14)
Use distributive property.
11x + 12y = 144
+ -11x - 22y = -154
_____________________ Add these together.
-10y = -10
Divide both sides by -10.
y = 1
Now substitute the value of y into one of
the original equations.
x + 2y = 14
x + 2(1) = 14
x + 2 = 14
- 2 -2 Subtract 2 from both sides.
x = 12
Now you have both values for x and y.
List them as an ordered pair
(in alphabetical order, of course).
(x,y)
(12,1)
This is answer choice D.
Always check the answer with BOTH equations.
11x + 12y = 144
11(12) + 12 (1) =144
132 + 12 = 144
144 = 144
It works.
2007-07-07 22:30:23 · answer #2 · answered by Brat Sheila♥♫ - the Precocious 6 · 0⤊ 0⤋
definitely D.
2007-07-07 22:06:37 · answer #3 · answered by yelah2992 1 · 0⤊ 0⤋