Answer:
B. 8 cm.
Step-by-step explanation:
The area of a rectangle is the length*width.
The area of the larger rectangle is 4*12=48.
The area of the smaller rectangle is 3*x=3x.
If the larger rectangle's area is twice that of the smaller rectangle, then we can say 48=2*3x.
Let's solve for x
48=2*3x
48=6x
x=8
This is a quadratic equation. There's a shortcut (two shortcuts really) called the Shakespeare Quadratic Formula (2b or -2b) applicable when the middle term is even:
OK, our problem is
Typically we'd write 
but the answers here don't so we won't either.
Answer: C and D
C.
2.5mi to someplace then coming back is 0
Answer:
x = 2 or 1/4
Step-by-step explanation:
-13/4 -x= 1/2x -1
Collect like terms
-13/4+1=1/2x+x
Using LCM
(-13+4)/4=(1+2x²)/2x
9/4=(1+2x²)/2x
Cross multiply
9(2x)=4(1+2x²)
18x=4+8x²
Turn into quadratic and solve
8x²-18x+4
Using formulae method
-b±(√b²-4ac)/2a
Where a=8, b= -18 and c=4
(-(-18)±(√(-18)²-4(8)(4))/2(8)
(18±(√324-128))/16
(18±√196)/16
(18±14)/16
(18+14)/16 or (18-14)/16
32/16 or 4/16
2 or 1/4
Replace n with 9 :
7 × 9 - 3 = 60
the answer is C.60
