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3 years ago

Which expression has an estimated product of 45?44.7x2.17.5x848.7x5.2838.1 x 7.3

Mathematics

2 answers:

Monica [59]3 years ago

7 0

Answer:

8.7 × 5.28 has an estimated product of 45.

Step-by-step explanation:

44.7 × 2.1 doesn't work because 44.7 is nearly 45 by itself, so doubling it wouldn't work.

7.5 × 84 doesn't work either because 84 is way past 45, so it can't work.

38.1 × 7.3 also doesn't work because 38 multiplied by 7 couldn't get anywhere near 45.

Anni [7]3 years ago

6 0

Answer: 8.7 x 5.28

We have to find that expression , which has an estimated product of

1.→44.7 x 2.1

2.→7.5 x 8.4

3.→8.7 x 5.28

4.→38.1 x 7.3

We will start from option 1.

→44.7 x 2.1

44.7 when estimated to nearest tenth=45

2.1, when estimated to nearest tenth=2

44.7 × 2.1=45×2=90

Option 2

7.5 x 8.4

7.5 when estimated to nearest tenth=8

8.4, when estimated to nearest tenth=8

⇒7.5 × 8.4=8×8=64

Option 3

8.7 × 5.28

8.7, when estimated to nearest tenth=9

5.28, when estimated to nearest tenth=5

⇒8.7 × 5.28=9×5=45

Option D

38.1 × 7.3

38.1 when estimated to nearest tenth=38

7.3, when estimated to nearest tenth=7

⇒38×7=266

Option C:⇒8.7 × 5.28 has an estimated product of 45

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Topic: The Quadratic Formula

Finger [1]

Answer:

Step-by-step explanation:

The quadratic formula for a equation of form

ax²+bx + c = 0 is

$x= \frac{-b +- \sqrt{b^2-4ac} }{2a}$

For the first equation,

x²+3x-4=0,

we can match that up with the form

ax²+bx + c = 0

to get that

ax² = x²

divide both sides by x²

a=1

3x = bx

divide both sides by x

3 = b

-4 = c

. We can match this up because no constant multiplied by x could equal x² and no constant multiplied by another constant could equal x, so corresponding terms must match up.

Plugging our values into the equation, we get

$x= \frac{-3 +- \sqrt{3^2-4(1)(-4)} }{2(1)} \\= \frac{-3+-\sqrt{25} }{2} \\ = \frac{-3+-5}{2} \\= -8/2 or 2/2\\= -4 or 1$

as our possible solutions

Plugging our values back into the equation, x²+3x-4=0, we see that both f(-4) and f(1) are equal to 0. Therefore, this has 2 real solutions.

Next, we have

x²+3x+4=0

Matching coefficients up, we can see that a = 1, b=3, and c=4. The quadratic equation is thus

$x= \frac{-3 +- \sqrt{3^2-4(1)(4)} }{2(1)}\\= \frac{-3 +- \sqrt{9-16} }{2}\\= \frac{-3 +- \sqrt{-7} }{2}\\$

Because √-7 is not a real number, this has no real solutions. However,

(-3 + √-7)/2 and (-3 - √-7)/2 are both possible complex solutions, so this has two complex solutions

Finally, for

4x² + 1= 4x,

we can start by subtracting 4x from both sides to maintain the desired form, resulting in

4x²-4x+1=0

Then, a=4, b=-4, and c=1, making our equation

$x=\frac{-(-4) +- \sqrt{(-4)^2-4(4)(1)} }{2(4)} \\= \frac{4+-\sqrt{16-16} }{8} \\= \frac{4+-0}{8} \\= 1/2$

Plugging 1/2 into 4x²+1=4x, this works as the only solution. This equation has one real solution

7 0

3 years ago

Is this how you set up my equation?

muminat

Looks correct. :)...........

8 0

3 years ago

Read 2 more answers

3x + 2y = 12<br> y = x - 9

Lina20 [59]

Answer:

y=12/2

y=6

x=12/3

x=4

y= x-9

Y=4-9

y=5

6=5

6/5

1.2

5 0

2 years ago

A diagonal of a square is 36 feet long. What is the area of the square?

Rzqust [24]

So you can you the Pythagorean theorem to solve this problem.

if each side of the square is a certain length x, then the square is made up of two right triangles.

the sides adjacent to the right angle are length x while the hypoteneus is the diagonal whcih measures 36 feet.

a^2 + b^2 = c^2

x^2 + x^2 = 36^2

2x^2 = 1296

x^2 = 648

x = 25.456

area of a square = x^2 = 648 ft^2

3 0

3 years ago

write an expression that shows how you can multiply 9 x 475 using expanded form and the distributive property

kiruha [24]

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4 0

3 years ago

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Which expression has an estimated product of 45?44.7x2.17.5x848.7x5.2838.1 x 7.3​

Which expression has an estimated product of 45?44.7x2.17.5x848.7x5.2838.1 x 7.3