What is the solution of the system of equations: -2x+8y=-8 and 5x-8y=20 using elimination

x = 4 and y = 0

Step-by-step explanation:

Given expression:

         -2x + 8y = -8

           5x - 8y = 20

Now, to solve this problem by elimination, follow this procedure:

           -2x + 8y = -8     --- i

            5x - 8y = 20      --- ii

 Coefficient of y in both expression have similar values;

  Now, add equation i and ii;

         (-2x + 5x) + (8y -8y ) = -8 + 20

                3x = 12

  Divide both sides by 3;

                 x = = 4

Now, to find y; put x = 4 into equation i,

              -2(4) + 8y = -8

                -8 + 8y = -8

      Add +8 to both sides of the expression;

                -8 + 8 + 8y = -8 + 8

                              8y = 0

                                 y = 0

3201

step-by-step explanation:

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional