Xiao was mistake because 3(20+30) still can divide by 10. The sum is 30(2+3)
Answer:
17 m
Step-by-step explanation:
As shown in the figure,
is the ground level,
is the old level of water which was at 20 m below ground level,
is the new level of water which is 5m above of old level. The height of wall of the well, 1.20 m, and the the pelly at 80 cm =0.80 m, has been shown too.
The minimum length of the rope is equal to the distance between the pully and the new water level, indicated by the length
in the figure.
So, 
Hence, Raghu must use a rope having the minimum length 17 m to draw water from the well.
Sum of 2 perfect cubes
a³+b³=(a+b)(x²-xy+y²)
so
x³+4³=(x+4)(x²-4x+16)
set each to zero
x+4=0
x=-4
the other one can't be solveed using conventional means
use quadratic formula
for
ax^2+bx+c=0
x=

for x²-4x+16=0
x=

x=

x=

x=

x=

x=

the roots are
x=-4 and 2+2i√3 and 2-2i√3
Answer:
8 and 5/8
Step-by-step explanation:
The question is just subtraction of fractions. First, you subtract the whole numbers. 10-2=8. Then you subtract the fractions. To do this, you have to make them equivalent. Just multiply the 1/4 by 2 and you get 2/8. Now, 7/8 - 2/8 = 5/8. Your final answer is 8 and 5/8