Answer:
A
Step-by-step explanation:
Answer:
x=1+2√2 or x=1−2√2
Step-by-step explanation:
Let's solve your equation step-by-step.
3x2−6x=21
Step 1: Since the coefficient of 3x^2 is 3, divide both sides by 3.
3x2−6x
3
=
21
3
x2−2x=7
Step 2: The coefficient of -2x is -2. Let b=-2.
Then we need to add (b/2)^2=1 to both sides to complete the square.
Add 1 to both sides.
x2−2x+1=7+1
x2−2x+1=8
Step 3: Factor left side.
(x−1)2=8
Step 4: Take square root.
x−1=±√8
Step 5: Add 1 to both sides.
x−1+1=1±√8
x=1±√8
x=1+2√2 or x=1−2√2
Answer:
The area is 200 ft^2
Step-by-step explanation:
The perimeter is 60 and the windth is twice larger, so the lenght is 10 ft and the width is 20 ft.
10x20= 200ft^2
Area=legnth times width=31
the frame must go around the frame with equal legnth, x
so
the total area (meaning the frame +picture) is 5+x by 6+x
31=(5+x)(6+x)
expand
31=30+11x+x^2
minus 31 both sides
0=-1+11x+x^2
x^2+11x-1=0
answer is third one
