Sumone help me setp by steeepppp ::)) ---Solve the system, using substitution. Write the solution as an ordered pair leaving no spaces, or write no solution or infinitely many solutions; Example: (2,1)

2x + 3y = 4 and x - 2y = -5

Question

Sumone help me setp by steeepppp ::)) ---Solve the system, using substitution.  Write the solution as an ordered pair leaving no spaces, or write no solution or infinitely many solutions; Example: (2,1)

2x + 3y = 4 and x - 2y = -5

amistre64 · Answer

what is you substitution value?

anonymous · Answer

3y?

amistre64 · Answer

not quite; 

that x-2y=-5  looks like we can solve it for "x" the easiest

amistre64 · Answer

what would a "value" for x be using that equation?

anonymous · Answer

2.58,1.25

anonymous · Answer

x=-7

anonymous · Answer

if someone is trying to explain and teach something, its a little rude to just throw out answers like that.

amistre64 · Answer

the word "value" here is not to imply a solid value such as -7 or 13 or any number; but a value in terms of y

x -2y = -5 ; lets add 2y to each side
   +2y   +2y
----------
   x = 2y-5  ; whatever y equals this is the value for x

anonymous · Answer

@Joemath Tru that! But everybdy is trying to help tho.

anonymous · Answer

3x+3y=4
becomes
x=(4/3)-y
substitude into equation 2
(4/3)-y-2y=-5
basic math
y=1.25
substitude the answer into equation 1
x=2.58

amistre64 · Answer

the process is more important the the numbers; the numbers always change while the process remains the same

amistre64 · Answer

do you see how I got a value for x, in terms of y?

anonymous · Answer

@amister64 Yes .

amistre64 · Answer

good, because that is the important step in substitutions; now we can use that "value" in the other equation and just have to solve for "y" alone

amistre64 · Answer

x - 2y = -5

x = 2y-5
-------------------
2x + 3y = 4

2(2y-5) + 3y = 4  ; the rest is just algebring it into submission :)

anonymous · Answer

Then you add like terms right???

amistre64 · Answer

2(2y-5) + 3y = 4  ; distribute the 2 thru

4y -10 +3y = 4  ; combine like terms

7y -10 = 4  ; add 10 across
    +10  +10
------------
     7y = 14  ; and divide off the 7
      /7    /7
    --------
        y = 2

amistre64 · Answer

now that we have a solid value for "y"; y = 2 , we can find a good solid value for x.

recall that we determined a value for x as:

x = 2y-5 , now we know y=2 so plug it in

x = 2(2) - 5

x = 4-5 = -1

amistre64 · Answer

its always good to include as a last step to dbl chk your work

amistre64 · Answer

an easy way to check is simply: http://www.wolframalpha.com/input/?i=2x+%2B+3y+%3D+4+and+x+-+2y+%3D+-5 :)

anonymous · Answer

Thanks Alot : ))))

amistre64 · Answer

youre welcome; hope it helped ;)

so to wrap it up; your answer should be:  (-1,2) i believe

anonymous · Answer

Ok