PLEASE HELP!! if f(x)= 2x^2-11, find f(4)

Mathematics

2 answers:

Lemur [1.5K]3 years ago

4 0

Answer: f(4) = 21

Step-by-step explanation:

2(4)^2-11

4^2 = 16

2(16)-11

Multiply 2 and 16

32 - 11

Subtract

goldenfox [79]3 years ago

4 0

Answer:

Step-by-step explanation:

f(x)= 2x^2-11

Let x= 4

f(4)= 2*4^2-11

= 2 * 16 - 11

= 32 -11

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kaheart [24]

Answer:

See proof below

Step-by-step explanation:

We will use properties of inequalities during the proof.

Let $y\in (x-\epsilon,x+\epsilon)$ . then we have that $x-\epsilon$ . Hence, it makes sense to define the positive number delta as $\delta=\min\{x+\epsilon-y,y-(x-\epsilon)\}$ (the inequality guarantees that these numbers are positive).

Intuitively, delta is the shortest distance from y to the endpoints of the interval. Now, we claim that $(y-\delta,y+\delta)\subseteq (x-\epsilon,x+\epsilon)$ , and if we prove this, we are done. To prove it, let $z\in (y-\delta,y+\delta)$ , then $y-\delta$ . First, $\delta \leq y-(x-\epsilon)$ then $-\delta \geq -y+x-\epsilon$ hence $z>y-\delta \geq x-\epsilon$

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