Answer:
35cm
Step-by-step explanation:
Given data
Length= 21cm
Width= 28cm
Diagonal= ???
Applying Pythagoras theorem
D^2= L^2+W^2
D^2= 21^2+28^2
D^2= 441+784
D^2= 1225
D= √1225
D= 35cm
Hence the diagonal is 35cm
Answer:
The student incorrectly simplified 10ab root 2a + 20a root 2a
Step-by-step explanation:
It should be 121, or +4 or -4 from that. But I am pretty sure it is 121
Given:
Consider the given equation is

To find:
The values of x.
Solution:
We have,

Taking square root on both sides, we get


Adding 18 on both sides, we get


Now,
and 
and 
Therefore, the correct option is A.