Answer:
Option A is correct, i.e. x = -3, x = 7.
Step-by-step explanation:
Given the equation is x² -4x -21 = 0.
We can compare it with general quadratic equation i.e. ax² +bx +c =0.
then a = 1, b = -4, c = -21.
We can use Quadratic formula as follows:-
x = ( -b ± √(b²-4ac) )/2a
x = ( +4 ± √(16-4*1*-21) )/2*1
x = ( +4 ± √(16+84) )/2
x = ( +4 ± √(100) )/2
x = ( +4 ± 10 )/2
x = (4+10)/2 or x = (4-10)/2
x = 14/2 or x = -6/2
x = 7 or x = -3
Hence, option A is correct, i.e. x = -3, x = 7.
Answer:
The variance of the given data is 106.9667
Step-by-step explanation:
The variance, S² of a sample is given by the expression;
Where:
= One of the observations
= The mean of the observations
n = Number in the sample = 6
The mean = Σ/n = (26 + 32 + 29 + 16 + 45 + 19
)/6 = 167/6 = 27.833
Therefore, we have;
S² = ((26 - 27.833)²+(32 - 27.833)²+(29 - 27.833)²+(16 - 27.833)²+(45 - 27.833)²+(19 - 27.833)²)/(6 - 1) = 106.9667.
Answer:
64
Step-by-step explanation:
56/7 = 8
8*8 = 64
64 tests
Answer:
100 Sq. =80 SQ. +60 SQ.
10000=6400+3600
10000=10000
yes,given length can form right angle triangle.
Answer:
2 - 0.5 i
Step-by-step explanation:
proof
