about 70,000 people live in a circular region with a 30-mile radius. find the population density in people per square mile.
1 answer:
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I"m guessing you mean
add 5 to both sides
square both sides
x+9=x²+18x+81
minus x+9 both sides
0=x²+17x+72
factor
what 2 numbres multiply to get 72 and add to get 17?
8 and 9
0=(x+8)(x+9)
set to zer
0=x+8
x=-8
x+9=0
x=-9
test each
1-5=-4
-4=-4
true
-5=-5
true
the solutions are x=-9 and -8
add 5 to both sides
square both sides
x+9=x²+18x+81
minus x+9 both sides
0=x²+17x+72
factor
what 2 numbres multiply to get 72 and add to get 17?
8 and 9
0=(x+8)(x+9)
set to zer
0=x+8
x=-8
x+9=0
x=-9
test each
1-5=-4
-4=-4
true
-5=-5
true
the solutions are x=-9 and -8