Solve using substitution method 4a + 20b=8, 8a= -40b+ 16?

4a + 20b = 8

8a = -40b + 16

We can solve for 4a for the second equation and substitute that for the first to solve for b!

8a/2 = (-40b + 16)/2

4a = -20b + 8

Substituting for the first equation..

-20b + 8 + 20b = 8

8 = 8

8 = 8 shows that both equations are congruent. Hence, there are infinite solutions.

I hope this helps!

4a + 20b = 8

8a = -40b + 16

from the 1st equation

4a = -20b + 8

a = -5b + 2

substitute the obtained (from the 1st equation) value of the unknown (a) in the 2nd equation

8(-5b + 2) = -40b + 16

-40b + 16 = -40b + 16

0 = 0

THE SYSTEM HAS INFINITE NUMBER OF SOLUTIONS

well all I know is that there is an infinite number of solutions because the equations are equal

so basically its like two lines one on the other

4a+20b=8

8a+40b=16, you can simplify and its going to give you the same equation

To make it easier, let's simplify the equations...........

4a + 20b = 8

a + 5b = 2

8a= -40b + 16

a = - 5b + 2

a + 5b = 2, which (in case you did not spot this earlier) is the same as the first equation. If that is all you know, the number of possible solutions is infinite

Zersek has given you a good start.

4a + 20b = 8 or dividing by 4 gives us : a + 5b = 2 or you could say a = 2 - 5b or the other way round

5b = 2- a and therefore b = (2-a)/5

Take your pick dear.

divide the first equation by 4 and the second equation by 8 to simplify so now you have:

a+5b=2 and a=-5b+2

looking at both equations they are the same, by adding 5b to both sides of the second equation you get; a+5b=2

since both equations are the same, the solutions are infinite, ex: if a=2, then b=0

if a=1, then b=1/5, and so on

take the 1st equation and divide everything by 4

a+5b=2

a=2-5b

substitute into 2nd equation

8(2-5b)=-40b+16

16-40b=-40b+16

16-40b=16-40b

b can be anything

CHEATER!!!!