5x+7y=142 3x-4x=261?

Answer 1

3x-4x= 261
x= -261

5*(-261)+7y=142
7y=142+1305
y=1447/7
y=206.71

Answer 2

1) 5x+7y=142 solving for variable x
Simplifying
5x + 7y = 142

Solving
5x + 7y = 142

Move all terms containing x to the left, all other terms to the right.

Add '-7y' to each side of the equation.
5x + 7y + -7y = 142 + -7y

Combine like terms: 7y + -7y = 0
5x + 0 = 142 + -7y
5x = 142 + -7y

Divide each side by '5'.
x = 28.4 + -1.4y

Simplifying
x = 28.4 + -1.4y

2) Solving for variable 'y'
Simplifying
5x + 7y = 142

Solving
5x + 7y = 142

Move all terms containing y to the left, all other terms to the right.

Add '-5x' to each side of the equation.
5x + -5x + 7y = 142 + -5x

Combine like terms: 5x + -5x = 0
0 + 7y = 142 + -5x
7y = 142 + -5x

Divide each side by '7'.
y = 20.28571429 + -0.7142857143x

Simplifying
y = 20.28571429 + -0.7142857143x

3) or you can substitute the x value straight into the equation and solve for y etc..


4) Solving 3x + -4x = 261
Simplifying
3x + -4x = 261

Combine like terms: 3x + -4x = -1x
-1x = 261

Solving
-1x = 261

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Divide each side by '-1'.
x = -261

Simplifying
x = -261

Answer 3

If -x = 261
so,
5(-261) + 7y = 142
-1305 + 7y = 142
7y = 142 + 1305
7y = 1447
y = 1447 : 7
y = 206,7
x = -261
y = 206,7

Answer 4

3x-4x=261
-x=261
x=-261

5x+7y=142
Substitute x=-261
5*(-261)+7y=142
-1305+7y=142
7y=142+1305
7y=1447
y=1447/7
y=206.71

Therefore x=-261 & y=206.71

Answer 5

Another way of thinking of this - I was taught by my teacher once of imagining the = sign as a bridge, and you have to get each of the different 'objects' (in this case similar variables such as all 'x' together) onto each side of the bridge... BUT whenever they CROSS THE BRIDGE, they 'change sides' - and so TURN INTO ITS OPPOSITE (or if its a function turn into its 'anti'-function). So using this idea, firstly you might decide to get all the numbers (constants) on the right hand side and all the 'x' terms on the left. This can be done in whichever order you like, as long as you remember to apply the basic rules... 5x + 2 = 3x + 24 Move +2 to the RHS 5x = 3x + 24 - 2 Move 3x to the LHS 5x - 3x = 24 - 2 Now We have similar terms collected on each side, we can simplify them by basic addition and subtraction: (5 - 3)x = 24 - 2 2x = 22 Now there is only one term of each type on each side of the =, we can find out what x is (that's 1x) by moving the *2 over, as 2x = 2*x = x*2. So replacing 2x with 2*x we get... x*2 = 22 Moving *2 over we get /2 (basic Multiplications always change to Divisions) x = 22 / 2 x = 11 END : You've solved the equation!

Answer 6

5x + 7y =142.......(1) 3*(1) gives 15x + 21y =426...........(3)
3x - 4y = 261........(2) 5*(2) gives 15x -20y = 1305..........(4)
(3) - (4) gives 41y = -879 or y = -21.43902439
Use y in (4) gives 15x = 1305 -428.7804878 or x = 876.2195122/15 = 58.41463415
Check in both (1) and (2) to make sure. x = 58.41463415; y = -21.43902439;

Answer 7

I'll answer this assuming your equations should be
5x+7y=142 (1)
3x-4y=261 (2)

(1) x 4 and (2) x 7 gives
20x+28y=580 (3)
21x-28y=1827 (4)

(3) + (4) gives
41x=2407
x=58.71 (2dp)

subst x = 2407/41 into (1) gives
y = -21.65 (2dp)

Answer 8

I am going to assume that you have 2 separate problems there. 5x + 7y = 142 and that the second one is supposed to be 3x - 4y = 261

If that is the case, the first one is x = 28.4 - 1.4 y
or y = 20.28 - .72x

The second one is x = 87 + 1.33 y

Answer 9

second equation you can write
-x=261=>x= - 261
put it into first equation
5(-261)+7y=142
-1305+7y=142
7y=1447
y=(1447/7)
solution is x=-261
y=1447/7
good luck

Answer 10

Multiply the first question by -3 and the second by 5 and then add them,
-15x-21y=-426
++15x-20y=1305
=>-41y=879
=>y=-21.439
=>x=[142-7(-21.439)]/5
=>x=58.4146