An indirect proof has been successful if you reach a contradiction of a known fact. a. true b. false c. cannot tell

True

Step-by-step explanation:

First we must understand the difference between direct and indirect proof

A direct proof assumes that the hypothesis of a conjecture is true, and then uses a logical well defined arguments  to prove that the conclusion of the conjecture is true.

An indirect proof assumes that it is not true and hence relies  on a contradiction to prove , and then running into a contradiction proving that the conjecture must be true.

Thus we assume a contradiction and proceed then we get a wrong conclusion stating that our assumption is false.

Thus a) True.

f(x)=2/3x-8, which give g(x) the greatest value.

step-by-step explanation:

region b will make the inequalities y < 2x + 1 and y > -x - 2 true ⇒ answer a

step-by-step explanation:

* lets study the graph and the inequality to solve the question

- the inequality y > -x - 2

∵ the form of the inequality is y > mx + c , m is the slope of the line

  and c is the y-intercept (the line intersect y-axis at point (0 , c)

∴ c = -2 that means the line intersect the y-axis at point (0 , -2)

∵ the sign of the inequality is >

∴ we shad the part over the line

  region a and b

- the inequality y < 2x + 1

∵ the form of the inequality is y > mx + c , m is the slope of the line

  and c is the y-intercept (the line intersect y-axis at point (0 , c)

∴ c = 1 that means the line intersect the y-axis at point (0 , 1)

∵ the sign of the inequality is <

∴ we shad the part under the line

  region b and c

∵ the common region between the two lines is region b

∴ region b will make the inequalities y < 2x + 1 and y > -x - 2 true