English Deutsch Français Italiano Español Português 繁體中文 Bahasa Indonesia Tiếng Việt ภาษาไทย
All categories

Need help with basic algebra

2006-08-20 17:17:59 · 24 answers · asked by Patrick R 1 in Education & Reference Homework Help

24 answers

first method: substitution
x+y=4
x=4-y---------1
x-y=10
x=10+y-------2
substitute 1-->2
4-y=10+y
-2y=6
y=6/-2
y=-3

second method: elimination
x+y=4-------1
x-y=10------2
minus 2 by 1
x+y=4
(-) x-y=10
------------->x-x=0, y-(-y)=2y, 4-10=-6
2y=-6
y=-6/2
y=-3

moreover, you can use back one out of two of the equation to find x when y=-3.
eg. when y=-3
x+y=4
x+(-3)=4
x=7

2006-08-20 17:32:09 · answer #1 · answered by Marushka 2 · 0 1

7

2006-08-21 00:22:42 · answer #2 · answered by Neutro 4 · 0 0

x + y = 4
x - y = 10
-----------
2 x + y - y = 4 + 10 (y -y = 0)
2 x = 14 ==> x = 7

7 + y = 4 ==> y = 4 - 7 = - 3

S= {x = 4; y = -3}

2006-08-22 06:05:41 · answer #3 · answered by bebevampire 2 · 0 0

x=-3
first you have to set it up to find y with the information that you already know.

x-y=10, so x=10+y

and then put that value of x into the first equation,
(10+y)+y=4 ---> 10+2y=4--> 2y=-6--> y=-3

(and x=7)

2006-08-21 00:25:56 · answer #4 · answered by sm2shakedown 2 · 0 0

x+y=4
x=4-y

therefore (4-y) - y = 10

so 4 - 2y = 10
-2y= 6
- y = 3
therefore y = -3

2006-08-21 00:24:31 · answer #5 · answered by michael2003c2003 5 · 0 0

make x-y=10 with one variable.

x=y+10

plug that in x+y=4

(y+10)+y=4
2y+10=4
-10 =-10
2y=-6
y=-3

plut that in the first eqution.

x-(-3)=10
x+3=10
x=7

2006-08-21 00:24:47 · answer #6 · answered by gnomef0cker 3 · 0 0

use elimination method
2x = 14
then get x = 7,
substitute to one of the equations
7 + y = 4
transpose 7 then y =-3

2006-08-21 01:48:22 · answer #7 · answered by -xue- 3 · 0 0

x+y=4
x-y=10
When you combine them (addition), the y's cancel out so you're left with:
2x = 14
Divide both sides by 2:
x=7
Plug it into the original equation:
7+y=4
Subtract 7 from both sides:
y=-3

Check with the equations:
x+y=4
7+(-3)=4
4=4

x-y=10
7-(-3)=10
10=10

2006-08-21 00:29:07 · answer #8 · answered by Anonymous · 0 0

Solve one your equations for x or y.
x-y =10
add y to both sides
x=10+y
now you can substitute your new value for x in the other equation.
10+y +y = 4
10 +2y =4
subtract 10 from both sides
2y = -6
divide by 2
y = -3

Hope that helps.

2006-08-21 00:23:44 · answer #9 · answered by goodlittlegirl11 4 · 0 0

y=-6

2006-08-21 00:22:17 · answer #10 · answered by aznxpranksta69 4 · 0 0

fedest.com, questions and answers