Answer:
9
Step-by-step explanation:
7r+18=r²
r²-7r-18=0
factorizing
r²+2r-9r-18=0
r(r+2)-9(r+2=0
(r-9)(r+2)=0
r-9=0
r=9
check
(r²)=(9*9)=81
7r+18=7(9) + 8=81
Answer:
5,5 -5,5
Step-by-step explanation:
If this does not help you im sorry
Answer: line N
Lenght of XY: 3
Step-by-step explanation:
The line N splits <u>XY</u> into two parts
5x+8=9x+12
-9x on each side
-4x+8=12
-8 on each side
-4x=4
divide by -4 on each side
x=-1
Answer: 117.5 seconds
Step-by-step explanation:
Given : It takes you 47 seconds to walk from the first (ground) floor of a building to the third floor.
Since from first floor to third , a person need to pass two levels of staircase.
We assume that the person walk at the same pace and the height of all floors are same.
The time taken to pass each level = (Time taken to pass 2 levels) ÷ 2
= (47 seconds) ÷ (2) = 23.5 seconds
Also, the from first floor to sixth floor , a person need to pass 5 levels of staircase.
Then, the time taken to pass each level = 5 x (Time taken to pass one level)
= 5 x 23.5 =117.5 seconds
Hence, it will take 117.5 seconds to walk from the first floor to the sixth floor.
