SOLUTION: add or substitute this problem I do not know how or which to do Can you help? 10x+2y=7 y=5x+3

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Question 60419: add or substitute this problem I do not know how or which to do Can you help? 10x+2y=7 y=5x+3
Found 2 solutions by smik, praseena:
Answer by smik(40) About Me  (Show Source):
You can put this solution on YOUR website!
Good problem. You could essentially do substitution or elimination, but I'd advise on substitution for this one since it's well set up for that because it's given you "y = something".


Let's go through it step by step. We have the following equations:


10x%2B2y=7
y=5x%2B3


We can substitute the y in 10x+2y=7 using y=5x+3, which gives us:


10x%2B2%285x%2B3%29=7


We can expand this, add the like terms, and solve for x:


10x%2B10x%2B6=7
20x%2B6=7
20x=1
x=1%2F20


Now that we know what the value of 'x' is we can find the value of y, preferably using y=5x+3 (since that's the quickest way to get a value for y):


y=5%281%2F20%29%2B3
y=1%2F4%2B3
y=13%2F4


Hence, we know:
x=1%2F20
y=13%2F4


Hope this helped.

Answer by praseena(37) About Me  (Show Source):
You can put this solution on YOUR website!

10x+2y=7 and
y=5x+3
------------------------------------------------------------------------
y=5x+3
substitute the value y = 5x + 3 in the first equation
==> 10x + 2*(5x+3) = 7
10x + 2*5x + 2*3 = 7
10x + 10x + 6 = 7
20x+6 = 7
subtract 6 from both sides of the equation
==> 20x = 1
==> x = 1/20
Now substitute the value, x = 1/20 in second equation(you can substitute the value of x in first equation also)
==> y = 5* 1/20 + 3
==> y = 4 + 3
==> y = 7
so the solution of the given equations are x = 1/20 and y = 7
bye.