Answer:
The equal is valid for x≤ 5/2
Step-by-step explanation:
sqrt(4x²-20x+25)=5-2x
Square both sides
(sqrt(4x²-20x+25))^2=(5-2x)^2
Foil the term on the right (5-2x)(5-2x) = 25 -10x-10x+4x^2 = 25 -20x+4x^2
(4x²-20x+25)=25-20x+4x^2
The left side is equal to the right side
We need to check for extraneous solutions
The break point is 5-2x =0
5 =2x
x =5/2
Check x < 5/2
Let x=0
sqrt(4x²-20x+25)=5-2x
sqrt(25)=5
True
Check x=5/2
sqrt(4x²-20x+25)=5-2x
sqrt(4(25/4)-20*5/2+25)=5-2(5/2)
sqrt(25-50+25)=5-5
0=0
True
Check x>5/2
Let x=10
sqrt(4x²-20x+25)=5-2x
sqrt(4*100-20*10+25)=5-2*10
sqrt(400-200+25)=5-20
sqrt(225) = -15
15 does not equal -15
False
The equal is valid for x≤ 5/2
