Answer:
x=10 and y=12
Step-by-step explanation:
To solve this quadratic equation we will use two method
1. Elimination method
2. substitution method
first of we use elimination method
we either eliminate x or y
we will be eliminating y
83x-20y=590..........(eq1)
60x+18y=816...........(eq2)
y will be eliminated by multiplying
(eq1) by 9
(eq2) by 10
which will give
747x-180y=5310.........(eq3)
600x-180y=8160.........(eq4)
see that y has the same value that is (-180y and +180y)
so to eliminate y completely you have to add eq1 and eq2 because if you don't add them together you wont eliminate y
747x-180y=5310
+
600x+180y=8160
=
1347x+0=13470
1347x=13470
x=13470/1347
x=10
Now to find y we use substitution method ie put x=10 in any of the equation above(eq1,eq2,eq3, eq4) you will get the same answer
eq1
83x-20y=590..... where (x=10)
83(10)-20y =590
830-20y=590
like terms
-20y=590-830
-20y= -240
divide both sides with -20
y= -240/-20
y=12
OR
eq2
60x+18y=816..... where x=10
60(10)+18y=816
600+18y=816
like term
18y=816-600
18y=216
y=216/18
y= 12
or eq3 or eq4 you will still get the same answer......
