Answer:
(5,-3)
Step-by-step explanation:
9x+2y=39
6x+13y=-9
---------------
117x+26y=507
12x+26y=-18
----------------------
105x=525
x=5
Substitution
9(5)+2y=39
45+2y=39
2y=-6
y=-3
Answer:
x=-0.7
Step-by-step explanation:
7x+1.1=-3.8
subtract 1.1 on both sides
7x=-4.9
divide both sides by 7
x=-0.7
Answer:
52
Step-by-step explanation:
Given that :
Mean (m) = 78
Standard deviation (s) = 13
Score that is 2 standard deviations below the mean
Using the relation :
Zscore = (x - m) / s
2 standard deviations below the mean means a Zscore of - 2
Hence,
-2 = (x - 78) / 13
Cross multiply
-2 * 13 = x - 78
-26 = x - 78
x = - 26 + 78
x = 52
Score which is 2 standard deviations below the mean is 52
The total angle sum of a triangle is 180°
As such, 180= 78 + 2s +4s
102= 6s
s=17
