Answered

IDNStudy.com, ang perpektong platform para sa malinaw at eksaktong mga sagot. Tuklasin ang malalim na sagot sa iyong mga tanong mula sa aming komunidad ng mga bihasang propesyonal.

What is the answer on
2x+4y=12
3x+y=9
using elimination method


Sagot :

[tex] \left \{ {2x + 4y =12} \atop {3x + y = 9}} \right. [/tex]

Think of a number that if you multiply it by the equation would eliminate one variable.

So in this case, I'll use the equation:
 
   3x + y = 9

What number should be multiplied by the equation above that when you combine it with 2x + 4 = 12 would eliminate one variable?

     2x + 4y =12 
   (3x + y = 9) -4 ⇒ -12x - 4y = -36
 
   2x + 4y = 12
  -12x - 4y = -36
 -----------------------
   -10x = -24
 
   -10x    -24               24                                12
  ------- = -----  ⇒   x = ----- (lowest term) ⇒ x =  ----
   -10      -10               10                                 5

(Now substitute to find y)

2x + 4y = 12

2(12/5) + 4y = 12

24/5 + 4y = 12

I want to remove the fraction part so I'll find for their lcd

(24/5 + 4y = 12) 5

24 + 20y = 60

20y     36           36              9
-----  = ---- ⇒ y = -----  ⇒ y = -----
20       20           20              5

CHECK:

3x + y = 9

3(12/5) + 9/5 = 9

36/5 + 9/5 = 9

45/5 = 9

9 = 9         

Check the attachment below =) 
View image Bellalesse