9514 1404 393
Answer:
135°
Step-by-step explanation:
Lines L and M are not shown as parallel, but we have to assume they are if we're to answer this question. That makes angle 2 and the one marked 135° alternate interior angles, hence congruent.
∠2 = 135°
_____
<em>Additional comment</em>
Angle 1 = 45° and x = 20.
The first 3 are examples of the difference of 2 squares so you use the identity
a^2 - b^2 = (a + b)(a - b)
x^2 - 49 = 0
so (x + 7)(x - 7) = 0
so either x + 7 = 0 or x - 7 = 0
giving x = -7 and 7.
Number 7 reduces to 3x^2 =12, x^2 = 4 so x = +/- 2
Number 8 take out GCf (d) to give
d(d - 2) = 0 so d = 0 , 2
9 and 10 are more difficult to factor
you use the 'ac' method Google it to get more details
2x^2 - 5x + 2
multiply first coefficient by the constant at the end
that is 2 * 2 = 4
Now we want 2 numbers which when multiplied give + 4 and when added give - 5:- -1 and -4 seem promising so we write the equation as:-
2x^2 - 4x - x + 2 = 0
now factor by grouping
2x(x - 2) - 1(x - 2) = 0
(x - 2) is common so
(2x - 1)(x - 2) = 0
and 2x - 1 = 0 or x - 2 = 0 and now you can find x.
The last example is solved in the same way.
Answer:
A) 15
Step-by-step explanation:
PEMDAS
20 / 4 + (6 * 2) - 2
take out the parenthesis which is P
20 / 4 + 12 - 2
there is no E
the go the rest of the way MDAS
5 + 12 - 2
17 - 2
15
Answer:
The specificity of this test is expressed as:________
70%.
Step-by-step explanation:
a) Data and Calculations:
TEST RESULTS Disease Present Disease Absent Total
Positive for Factor X 40 60 100
Negative for Factor X 10 140 150
Total 50 200 250
Negative for X and Disease Absent = 140/200 * 100
= 0.7 * 100
= 70%
b) The specificity refers to the percentage of people who test negative for a specific disease among a group of people who do not have the disease. No test is 100% specific because some people who do not have the disease X will test positive for it (false positive). Therefore, we are testing for the true negative, that the 140 people who tested out of the 200 people who do not have the disease.
