- 6x - 9y = - 21
6x + 8y = 20--------ADD
- y = - 1
y = 1
2x + 3 = 7
2x = 4
x = 2
x = 2 , y = 1
x = 2 y = 1
You can either substitute or use the addition/subtraction methods. Let's substitute, shall we?
(2x+3y)÷2 = (7)÷2
x+(3y)/2 = 7/2
x = (7/2)-(3y/2)
3x+4y = 10
3((7/2)-(3y/2))+4y = 10
(21/2)-(9y/2)+4y = 10
Multiply everything by negative 1
-(21/2)+(9y/2)-4y = -10
(9y/2)-4y = -10+(21/2)
(1/2)y = 1/2
2x+3(1) = 7
y=1
x=2
2x + 3y = 7 .....equation 1
3x + 4y = 10 .....equation 2
multiply equation1 by 3 and equation2 by 2
this makes the x coefficients the same
equation 1 becomes..... 6x + 9y = 21
equation 2 becomes..... 6x + 8y = 20
subtract your new (2) from your new (1), thus getting rid of your x's completely
>>> y = 1
you now have a value for y, you can substitute this into either of your original equations
(1) 2x + 3y = 7
>>>>
so, 2x + (3*1) = 7
((minus 3 from both sides of the equation))
((divide both sides by 2))
so x=2, and, y=1
Okay so multiply the first equation by -3 and the second equation by 2 then add:
-6x-9y=-21
6x+8y=20
So, -y = -1 or y = 1. Plug this into either equation to get the other variable: 3x+4(1) = 10 so 3x+4 = 10 or 3x=6 or
x=2.
so x=2, y=1
3 x (2x + 3y) = 6x + 9y = 21
2 x (3x + 4y) = 6x + 8y = 20
(6x + 9y) - (6x + 8y) = y = 1
substituting y = 1 in 2x + 3y = 7
therefore 2x = 4
x = 2 and y = 1
not great maths working but I hope you can follow the idea.
2x+3y=7 To solve to x you simply subtract 3y leaving 2x=7-3y Divide by 2 leaving x=7-3y/2. To solve for y, you do the same thing, but for y. Do the same for the other equation. Good luck and learn.
2x+3y = 7 ....(1)
3x+4y = 10....(2)
(1)*3... 6x+9y = 21 ...(3)
(2)*2... 6x+8y = 20 ...(4)
(3)-(4)... y = 1
sub y into (1) 2x + 3 = 7
Use elmination:
2x+3y=7(-3)
3x+4y=10(2)
__________
-y = -1
2x+3(1)=7
(2,1) is the answer
x=2 and y=1 because 2x2=4 and 3x1=3 which is 7
and 3x2=6 and 4x1=4 which is 10
so it is x=2 and y=1
hope this helps
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Answers & Comments
Verified answer
- 6x - 9y = - 21
6x + 8y = 20--------ADD
- y = - 1
y = 1
2x + 3 = 7
2x = 4
x = 2
x = 2 , y = 1
x = 2 y = 1
You can either substitute or use the addition/subtraction methods. Let's substitute, shall we?
(2x+3y)÷2 = (7)÷2
x+(3y)/2 = 7/2
x = (7/2)-(3y/2)
3x+4y = 10
3((7/2)-(3y/2))+4y = 10
(21/2)-(9y/2)+4y = 10
Multiply everything by negative 1
-(21/2)+(9y/2)-4y = -10
(9y/2)-4y = -10+(21/2)
(1/2)y = 1/2
y = 1
2x+3(1) = 7
2x = 4
x = 2
y=1
x=2
2x + 3y = 7 .....equation 1
3x + 4y = 10 .....equation 2
multiply equation1 by 3 and equation2 by 2
this makes the x coefficients the same
equation 1 becomes..... 6x + 9y = 21
equation 2 becomes..... 6x + 8y = 20
subtract your new (2) from your new (1), thus getting rid of your x's completely
>>> y = 1
you now have a value for y, you can substitute this into either of your original equations
(1) 2x + 3y = 7
>>>>
so, 2x + (3*1) = 7
2x + 3 = 7
((minus 3 from both sides of the equation))
>>>>
2x = 4
((divide both sides by 2))
>>>>
x=2
so x=2, and, y=1
Okay so multiply the first equation by -3 and the second equation by 2 then add:
-6x-9y=-21
6x+8y=20
So, -y = -1 or y = 1. Plug this into either equation to get the other variable: 3x+4(1) = 10 so 3x+4 = 10 or 3x=6 or
x=2.
so x=2, y=1
3 x (2x + 3y) = 6x + 9y = 21
2 x (3x + 4y) = 6x + 8y = 20
(6x + 9y) - (6x + 8y) = y = 1
substituting y = 1 in 2x + 3y = 7
2x + 3 = 7
therefore 2x = 4
x = 2 and y = 1
not great maths working but I hope you can follow the idea.
2x+3y=7 To solve to x you simply subtract 3y leaving 2x=7-3y Divide by 2 leaving x=7-3y/2. To solve for y, you do the same thing, but for y. Do the same for the other equation. Good luck and learn.
2x+3y = 7 ....(1)
3x+4y = 10....(2)
(1)*3... 6x+9y = 21 ...(3)
(2)*2... 6x+8y = 20 ...(4)
(3)-(4)... y = 1
sub y into (1) 2x + 3 = 7
2x = 4
x = 2
Use elmination:
2x+3y=7(-3)
3x+4y=10(2)
__________
-y = -1
y = 1
2x+3(1)=7
2x = 4
x = 2
(2,1) is the answer
x=2 and y=1 because 2x2=4 and 3x1=3 which is 7
and 3x2=6 and 4x1=4 which is 10
so it is x=2 and y=1
hope this helps
x = 2
y = 1