Solve the following system of equations 3x - 4y = 25 -2x + y = -10
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calendarEducator since 2008
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3x -4y = 25.........(1)
-2x + y = -10...........(2)
We will use the elimination method to solve.
Multiply (2) by 4.
==> -8x + 4y = -40
Now we will add to (1).
==> -5x = -15
Now we will divide by -5.
==> x = 3
Now, from (2) we will rewrite:
y= -10 + 2x
==> y= -10+2*3 = -10+ 6 = -4
==> y= -4
Then, the solution to the system is : x= 3 and y= -4 or the pair (3,-4).
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calendarEducator since 2010
write12,544 answers
starTop subjects are Math, Science, and Business
We have to solve the system of equations
- 3x - 4y = 25
- -2x + y = -10
3x - 4y = 25
=> 3x = 25 + 4y
=> x = ( 25 + 4y)/3
substitute in -2x + y = -10
=> -2 ( ( 25 + 4y)/3) + y = -10
=> ( 25 + 4y)/3 - y/2 = 5
=> 2( 25 + 4y) - 3y = 30
=> 50 + 8y - 3y = 30
=> 5y = -20
=> y = -20/ 5
=> y = -4
x = ( 25 + 4y)/3
=> (25 - 16) / 3
=> 9/3
=> 3
Therefore x = 3 and y = -4
3x - 4y = 25
-2x + y = -10
First, multiply everything on the second equation by 4.
By multiplying, your equation should look like
3x - 4y = 25
-8x + 4y = -40 now, add -4y with 4y ( so add 3x with -8x and 25 with -40 also )
-5x = -15 now divide both sides by -5
By dividing, your equation should look like
x = 3 which is your answer for " x "
Now plug 3 into one of the equation
-2 ( 3 ) + 4y = -10 multiply -2 with 3
By multiplying, your equation should look like
-6 + 4y = -10 now add 6 on both sides
By adding, your equation should look like
4y = -16 now divide both sides by 4
By dividing your equation should look like
y = -4 which is your answer for " y "
So your answer is x = 3 ; y = -4
-2x+y=-10
-2x+y+2x=-10+2x
y=-10+2x
3x-4(-10+2x)=25
3x+40-8x=25
-5x+40=25
-5x+40-40=25-40
-5x=-15
-5x/-5=-15/-5
x=3
3(3)-4y=25
9-4y=25
9-4y-9=25-9
-4y=16
-4y/-4=16/-4
y=-4
We'll multiply the 2nd equation by 4 and we'll solve the system using elimination:
3x - 4y - 8x + 4y = 25 - 40
-5x = -15
x = 3
We'll substitute x into the 2nd equation:
-2*3 + y = -10
We'll move the numbers alone to the right side:
y = 6 - 10
y = -4
The solution of the system is represented by the pair: (3 ; -4).
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