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3 years ago

How to do this ? Don’t understand it

Mathematics

1 answer:

riadik2000 [5.3K]3 years ago

7 0

X=y+3
-5x-4y=30
-------------------
Substitute y + 3 for x in -5x-4y=30
-5(y+3)-4y=30
-9y-15=30
----------------------------
Add 15 to each side
-9y-15+15=30+15
-9y = 45
-----------------------------------
Divide each side by -9
-9y ÷ -9 = 45 ÷ -9
y = -5
Now we solve for x
====================================================================
Substitute -5 for y in x = y + 3
x=-5+3
x = -2
----------------------
(-2,-5) is your answer

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