Questions on Algebra: Distributive, associative, commutative properties, FOIL answered by real tutors!

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Question 148001: I just can't seem to grasph how to figure x & y. Please help!!!
-4x + 3y = 10
5x - 7y = -32
5x =75
-2x -5y = 50
: I just can't seem to grasph how to figure x & y. Please help!!!
-4x + 3y = 10
5x - 7y = -32
5x =75
-2x -5y = 50

Answer by jim_thompson5910(9401) About Me  (Show Source):
You can put this solution on YOUR website!
I'll do the first one to get you started


# 1



Start with the given system of equations:


system(-4x + 3y = 10,5x - 7y = -32)


-4x + 3y = 10 Start with the first equation.


3y=10+4x Add 4x to both sides.


y=(10+4x)/(3) Divide both sides by 3 to isolate y.


y=(4/3)x+10/3 Simplify.


-------------------------------------------


5x - 7((4/3)x+10/3) = -32 Now plug in y=(4/3)x+10/3 into the second equation.


5x-(28/3)x-70/3=-32 Multiply.


3(5x-(28/cross(3))x-70/cross(3))=3(-32) Multiply both sides by the LCD 3 to clear any fractions.


15x-28x-70=-96 Distribute and multiply.


-13x-70=-96 Combine like terms on the left side.


-13x=-96+70 Add 70 to both sides.


-13x=-26 Combine like terms on the right side.


x=(-26)/(-13) Divide both sides by -13 to isolate x.


x=2 Reduce.


-------------------------------------------


Since we know that x=2, we can use this to find y.


-4x + 3y = 10 Go back to the first equation.


-4(2) + 3y = 10 Plug in x=2.


-8+3y=10 Multiply.


3y=10+8 Add 8 to both sides.


3y=18 Combine like terms on the right side.


y=(18)/(3) Divide both sides by 3 to isolate y.


y=6 Reduce.


So the answer is x=2 and y=6.


This means that the system is consistent and independent.


Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.


drawing(500,500,-8,12,-4,16,<BR>
grid(1),<BR>
graph(500,500,-8,12,-4,16,(10+4x)/(3),(-32-5x)/(-7)),<BR>
circle(2,6,0.05),<BR>
circle(2,6,0.08),<BR>
circle(2,6,0.10)<BR>
) Graph of -4x+3y=10 (red) and 5x-7y=-32 (green)