Subtract 16 to get
x^2 -25 = 0
Factor this as
(x -5)(x +5) = 0
The zero product property tells you the product will be zero when one of the factors is zero.
For x-5 = 0
x = 5
For x+5 = 0
x = -5
The appropriate choice is
3) x=-5 or x=5
Answer:
Step-by-step explanation:
<u>Temperatures given:</u>
<u>Descending order of the numbers is:</u>
Correct choice is E
Answer: x=-7/2 y=29/2
Steps:
Use the elimination method
Multiply -3x+y=4 by 5 to make the coefficient next to the y in both equations the same
5(-3x+y=4)
-15x+5y=20
Then, subtract to eliminate the y
-15x+5y=20
- -9x+5y=-1
= -6x=21
Divide both sides by -6 to isolate x
= x= -7/2
Next substitute -7/2 into x in one of the equations
-3(-7/2)+y=4
-21/2+y=4
Add 21/2 from both sides to isolate y
y=29/2
Notice that
y² - 20y + 100 = y² - 2•10y + 10² = (y - 10)²
Then
√(y² - 20y + 100) = y - 10
is equivalent to
√((y - 10)²) = y - 10
|y - 10| = y - 10
If y ≥ 10, then |y - 10| = y - 10, and
y - 10 = y - 10 ⇒ 0 = 0
so there are infinitely many solutions, y ≥ 10.
Otherwise, if y < 10, then |y - 10| = -(y - 10), and
-(y - 10) = y - 10 ⇒ 10 = -10
which is false, so there are no solutions in this case.
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