﻿ If x -12y = -210 and x - 6y = 90, then x =? - science mathematics
If x -12y = -210 and x - 6y = 90, then x =?

## If x -12y = -210 and x - 6y = 90, then x =?

[From: Mathematics] [author: ] [Date: 04-07] [Hit: ]
If x -12y = -210 and x - 6y = 90, then x =?......

If x -12y = -210 and x - 6y = 90, then x =?

-------------------------------------------------------

answers:
Wile E. say: 1) x - 12y = - 210
2) x - 6y = 90

Rewrite both equations in terms of x:

3) x = 12y - 210
4) x = 6y + 90

Since the the right sides both equal x, then they are equal to each other (Transitive Law of Math), so

12y - 210 = 6y + 90

Subtract 6y from both sides:

12y - 6y - 210 = 90

Add 210 to both sides:

12y - 6y = 210 + 90

Combine like terms:

6y = 300

Divide both sides by 6:

y = 50
¨¨¨¨¨¨¨¨

Sub 50 for y in either of the equations, I'll choose 4):

x = 6(50) + 90

Distribute the 6:

X = 300 + 90

Combine like terms:

X = 390
¨¨¨¨¨¨¨¨¨¨¨

Solution Set (390, 50)
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
-
Idealist say: x-12y=-210
x-6y=90
------------------
-(x-12y)=-(-210)
x-6y=90
-----------------------
-x+12y=210
x-6y=90
----------------
Add them.
6y=300
y=300/6=50
Substitute.
x-6(50)=90
x-300=90
x=90+300=390
Answer: (390, 50)
Therefore, x=390.
-
David say: The solutions to the given simultaneous equations are x = 390 and y = 50
-
Como say: --
x - 6y = 90
- x + 12y = 210_________add

6y = 300
y = 50

x - 300 = 90
x = 390

x = 390 , y = 50
-
Φ² = Φ+1 say: x = (-210×-6--12×90)/(1×-6--12×1) = (1260+1080)/(-6+12) = 2340/6 = 390

Note: The question only asks for the solution for x.
-
sepia say: x - 12y = -210
x - 6y = 90
2x - 12y = 180
x = 390, y = 50
-
? say: x -12y = -210
x - 6y = 90
------------------ -
....-6y = -300
....y = 50

x-6y = 90
x = 90 + 6y
x = 90 + 6(50)
x = 390...............ANS
-
khalil say: multiply the second by (-2) to eliminate (y)
x -12y = -210
-2x +12y = -180
add
-x = -390
x = 390
-
az_lender say: Evidently 6y = 300, so y = 50, and x = 390.
-
Morningfox say: The difference in those two equations is -12y - (-6y) = -210 - 90
Which is the same as -6y = -300. I hope you can work out the rest.
-

keywords: ,If x -12y = -210 and x - 6y = 90, then x =?
New
Hot
© 2008-2010 science mathematics . Program by zplan cms. Theme by wukong .