SOLUTION: in my homework it says to give the point that represents the intersections of the lines? i dont get how to solve the problem. i would like to know what is the equation or solution

Algebra ->  Expressions-with-variables -> SOLUTION: in my homework it says to give the point that represents the intersections of the lines? i dont get how to solve the problem. i would like to know what is the equation or solution       Log On


   

Question 131635: in my homework it says to give the point that represents the intersections of the lines? i dont get how to solve the problem. i would like to know what is the equation or solution to the problems so i can do the rest by myself.the problem is y=x and 4x+5y=9 how do u find where the intersections of the lines is
Found 2 solutions by stanbon, 067isa:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
y=x and 4x+5y=9
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You are looking for a pair of numbers that make both equations true.
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Since y = x, substitute x in place of y in the 2nd equation:
4x + 5x = 9
9x = 9
x = 1
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But y = x, so y = 1 also.
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The solution for the system is (1,1)
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If you graph the two equation they will intersect at (1,1).
graph%28400%2C300%2C-10%2C10%2C-10%2C10%2Cx%2C%28-4%2F5%29x%2B%289%2F5%29%29
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Cheers,
Stan H.

Answer by 067isa(13) About Me  (Show Source):
You can put this solution on YOUR website!
ok the intersection means in math where the two lines intersect each other.
so the point of the intersection staisfied both equation.
y=x " equation one"
4x+5y=9 " equation two"
so we can solve this by three ways Elimination or Sub. or graphying
i am going to do it by substution ok
so now , sub equation one in equation two
instead of y put x in the second equation
4x+5(X)=9
9x=9 divde both sides by 9
x=1 use either first or second equation to get the Y value because we looking for a point with both corodinates ok. since as i said at the beginning the point of intersection will statifeid both equation so no problems to sub. the value of X in either of these two equation
the first is easier
y=x
so we got x=1 therfore the y=1
so the point of the intersection is (1,1) Good Luck
try to sub the value of X in the second equatiion to find a surpise! the same answer for Y