answersLogoWhite

0


Best Answer

It looks like you have 2 simultaneous equations with 2 variables:

4x + 8y = 20 and -4x + 2y = -30. Solution is {x=7, y = -1}.

One way to solve:

Add the two equations together, combining like terms: (4x - 4x) + (8y + 2y) = 20-30 --> 0 + 10y = -10 --> y = -1. Substitute this into either of the original equations and solve for x=7, then check in the other equation to make sure you calculated correctly.

User Avatar

Wiki User

12y ago
This answer is:
User Avatar

Add your answer:

Earn +20 pts
Q: What is 4x plus 8y equals 20 - -4x plus 2y equals -30?
Write your answer...
Submit
Still have questions?
magnify glass
imp
Related questions

How do you do 2x plus y equals -12 -4x-2y equals 30?

2x+y=-12-4x-2y=30 x=-y/2+30, you plug this into -12-4x-2y=30 and get -12+2y-120-2y=30 which gives 2y-2y=162. This is not possible, so the equation is unsolvable.


What is the slope intercept form of the equation 5x plus 2y equals 30?

5x+2y = 30 2y = -5x+30 y = -2.5x+15 Therfore the slope is 2.5 and y the intercept is 15.


What is 15 plus 20 plus 20 plus 20 plus 35 plus 30 plus 35 plus 30 equals?

205


2y plus 3y-7y plus 4 equals 16?

2y+3y-7y+4=16 -2y=12y=-6Check it-12-18+42+4=16-30+46=1616=16


What is 3a equals 30 plus 30?

a = 20


What is -20 plus 30 equals?

10


Solve this using substitution x plus 2y equals 30 x2 plus y2 equals 900?

x+2y = 30 => x= 30-2y x2+y2 =900 (30-2y)2+y2 = 900 (30-2y)(30-2y)+y2 = 900 900-60y-60y+4y2+y2 = 900 5y2-120y = 0 y(5y-120) = 0 y = 0 or y= 24 Substitute the value of y into the original equations to find the value of x: Therefore: x = -18 and y = 24 Check: -18+48 = 30 and (-18)2+242 = 900


How to find elimination method for 3x - 4y equals 30 and 3x plus 2y equals 6?

Subtract: 3x - 3x - 4y - 2y = 30 - 6 ie -6y = 24 so y = -4 and x = 14/3


5x plus 20 equals 4x plus 30?

5x + 20 = 4x +30 5x - 4x = 30 - 20 x = 10


What is the x and y coordinates of these equations y equals 3x and 4x plus 2y equals 30?

4x + 2(3x) = 30 10x = 30 x= 3. Y= 9. (3,9)


3y plus 5 equals y-25?

3y+5=y-25 2y=-30 y= -15


What is 10 plus 20 plus 30 plus 40 plus 50?

10 plus 20 plus 30plus 40 plus 50 equals 150 because 50 plus 40 equals 90 plus 30 =120+20= 140 then + 10 = 150