5x-8y=1...(1)
3x+6y=-21...(2)
(1)*3:
15x-24y=3...(3)
(2)*5:
15x+30y=-105...(2)
(3)-(2):
15x-24y-(15x+30y)=3-(-105)
15x-24y-15x-30y=108
-54y=108
y=-2
Answer:
One Solution
Step-by-step explanation:
Trust me
Answer:
B. 88.8
Step-by-step explanation:
let x represent class y
(x+71.2)/2=80 multiply each side by 2
x+71.2=160 subtract 71.2 by both sides
x=88.8
or
trial an error
replace x with each of the numbers and see if it plugs in.
example:
(80.5+71.2)/2=80
151.7/2=80
75.85=80?
false. incorrect
another example:
(88.8+71.2)/2=80
160/2=80
80=80?
true. correct
Answer: 100
Step-by-step explanation: 10%
Answer:
Step-by-step explanation:
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