When applying indirect proofs, we assume the negation of the conclusion is true, and show that this assumption would lead to nonsense, or contradiction.
In our case we assume a is not smaller than 7, that is we assume a≥7.
a≥7 then, multiplying both sides by 3:
3a≥21, then, adding both sides 7:
3a+7≥28,
which is a contradiction because 3a+7 is smaller than 28.
So our assumption is wrong, which means the opposite of it is correct.
Answer: assume a≥7
Answer:
The probability is 0.044
Step-by-step explanation:
Step-by-step explanation:
Let p be the probability that the new principal’s performance is approved.
This is obtainable from the survey and it is 8/10 = 0.8
Let q be the probability that the new principal’s performance is disproved.
That will be;
1 - q = 1- 0.8 = 0.2
To calculate the probability that 14 parents names are chosen at random and they all
approve of the principal’s performance, we use the Bernoulli approximation of the binomial theorem.
That will be;
14C14 * p^14 * q^0
= 1 * 0.8^14 * 0.2^0
= 0.043980465111 which is approximately 0.044
Answer:
Step-by-step explanation:
Area of the figure = area of the down triangle + area of trapezium + area of the upper triangle
Down triangle:
Base b = 8 in
Height = 6 in
= 24 in²
Trapezium:
bases a = 4 in & b = 6 in
Height h = 5 in
= 25 in²
Area of the upper triangle:
Base b = 6 in
Height = (8 - 5) = 3 in
= 9 in²
Area of the figure = 24 + 25 + 9 = 58 in²
Answer:
The center is -1,5 and the radius is 2
Step-by-step explanation:
Subtract 22 from both sides of the equation. x 2 + y 2 + 2 x − 10 y = − 22 Complete the square for x 2 + 2 x . ( x + 1 ) 2 − 1 Substitute ( x + 1 ) 2 − 1 for x 2 + 2 x in the equation x 2 + y 2 + 2 x − 10 y = − 22 . ( x + 1 ) 2 − 1 + y 2 − 10 y = − 22 Move − 1 to the right side of the equation by adding 1 to both sides. ( x + 1 ) 2 + y 2 − 10 y = − 22 + 1 Complete the square for y 2 − 10 y . ( y − 5 ) 2 − 25 Substitute ( y − 5 ) 2 − 25 for y 2 − 10 y in the equation x 2 + y 2 + 2 x − 10 y = − 22 . ( x + 1 ) 2 + ( y − 5 ) 2 − 25 = − 22 + 1 Move − 25 to the right side of the equation by adding 25 to both sides. ( x + 1 ) 2 + ( y − 5 ) 2 = − 22 + 1 + 25 Simplify − 22 + 1 + 25 . ( x + 1 ) 2 + ( y − 5 ) 2 = 4 This is the form of a circle. Use this form to determine the center and radius of the circle. ( x − h ) 2 + ( y − k ) 2 = r 2 Match the values in this circle to those of the standard form. The variable r represents the radius of the circle, h represents the x-offset from the origin, and k represents the y-offset from origin. r = 2 h = − 1 k = 5 The center of the circle is found at ( h , k ) . Center: ( − 1 , 5 ) These values represent the important values for graphing and analyzing a circle.
