Answer: Correct two digit number= 24
Step-by-step explanation:
Let
x= tens digit (wrong one)
and y= zeroes digit
and z= tens digit (right one)
Now according to the statement,
(10x+y)² - (10z+y)² = 2340
Simplifying this we get
(x-z)(5x+y+5z)= 117= 1 * 3 * 3 * 13
So it could either be
x-z=1 or x-z=3
If we take the x-z=1
then 5x+y+5z=117
which is not possible as maximum value we can get from this is 99.
This leaves us with x-z=3
so 5x+y+5z= 39
Put x=3+z
We get,
y+10z= 24
Now as y and z both are single digits so the only possible numbers to fit these are y=4 and z=2.
Put z=2 in x=3+z , we get x=5
So the numbers become 10x+y= 54
and 10z+y= 24
Their sum is 54+24=78
Check
54²-24²= 2340 so it is correct.
I you're looking for the equation, it is
and If you need me to solve it, it is
Answer:
a. 60 centimeters
b. 67 centimeters
Step-by-step explanation:
a.
12 × 4 = 48
(6 × 4) ÷ 2 = 12
48 + 12 = 60
b.
7 × 10 = 70
(2 × 3) ÷ 2 = 3
70 - 3 = 67
determinant: 
(a) 
D<0 means there are no real roots. there are two complex roots with imaginary components.
(b) D=16+20=36>0
D>0 means there are two real roots
(c) D = 20^2-4*4*25 = 0
D=0 means there is one real root with multiplicity 2
