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4 years ago

14

If f(x) = x2 – 3x – 40 intersects the x-axis at points A and B, what is the sum of A and B?

1 answer:

Eduardwww [97]4 years ago

4 0

Answer:

3

Step-by-step explanation:

Intersections on the x axis occur when y = 0. f(x) is another term for y, so set f(x) equal to zero and solve for the two possible x's.

0 = x^2 - 3x - 40

0 = (x-8)(x+5)

By solving for x, you get 8 and -5. 8 and -5 added together will equal 3.

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The line $y = 3$ intersects the graph of $y = 4x^2 + x - 1$ at the points $A$ and $B$. The distance between $A$ and $B$ can be w

raketka [301]

Answer:

61

Step-by-step explanation:

Let's find the points $A$ and $B$ .

We know that the $y$ -coordinates of both are $3$ .

So let's first solve:

$3=4x^2+x-1$

Subtract 3 on both sides:

$0=4x^2+x-1-3$

Simplify:

$0=4x^2+x-4$

I'm going to use the quadratic formula, $x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$ , to solve.

We must first compare to the quadratic equation, $ax^2+bx+c=0$ .

$a=4$

$b=1$

$c=-4$

$\frac{-1 \pm \sqrt{1^2-4(4)(-4)}}{2(4)}$

$\frac{-1 \pm \sqrt{1+64}}{8}$

$\frac{-1 \pm \sqrt{65}}{8}$

Since the distance between the points $A$ and $B$ is horizontal. We know this because they share the same $y-coordinate$ .This means we just need to find the positive difference between the $x$ -values we found for the points of $A$ and $B$ .

So that is, the distance between $A$ and $B$ is:

$\frac{-1+\sqrt{65}}{8}-\frac{-1-\sqrt{65}}{8}$

$\frac{-1+\sqrt{65}+1+\sqrt{65}}{8}$

$\frac{2\sqrt{65}}{8}$

$\frac{\sqrt{65}}{4}$

If we compare this to $\frac{\sqrt{m}}{n}$ , we should see that:

$m=65 \text{ and } n=4$ .

So $m-n=65-4=61$ .

5 0

3 years ago

Read 2 more answers

A man buys a box of 100 apple in a market for $44. He sells all the apples for $0.5 each. What is his profit or loss? Loss =$ 44

zzz [600]

Answer:

Profit = $6

Step-by-step explanation:

The box of apple that the man bought contained 100 apples.

These 100 apples were gotten for $44

Then he sold the 100 apples for $0.5 each.

So sales price = 0.5 * 100 = $50

To know if he made profit or loss.

Sales price - cost price

$50 - $44

= $6

This man made profit of $6 from the sales of the apples from the calculation above.

4 0

3 years ago

SOLVE FOR BRAINLIST!!

Natasha_Volkova [10]

The correct answer is c

6 0

3 years ago

7 × (–3) × (–2)^2 =

skad [1K]

<span>7 × (–3) × (–2)^2
= </span>-21 × 4
= - 84

Hope it helps

5 0

3 years ago

Read 2 more answers

9k/65 = 1316/845<br> find k and show work

olga2289 [7]

Answer:

k= 1316/117

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers