All categories

3 years ago

Explain how using basic facts can help you find 10 X 20 X 30 X 40 mentally?

2 answers:

4 0

Take the left side of each number first. Do 1 x 2 x 3 x 4. That equals 24. Easy. Now, count the 0's in the equation which are 4 of them. Add the four zeros and to the 24 and that's your answer. 240,000

laiz [17]3 years ago

4 0

First you o 10*20 which is 200. Then multiply it by 30 that equals to 6000. And then multiply it by 40 that is 240,000.

You might be interested in

Why are the solutions to the proportions 50/x =10/20 and 10/50=20/x the same

ratelena [41]

With cross multiplication you can find that they are the same. In both equations, x would be 100.

5 0

3 years ago

Read 2 more answers

John can jog 3,000 yards in 15 minutes. Id she jogs at thw same rate, how many feet can she jog in 6 minutes

Kobotan [32]

3,000 y / 15 m
9,000 f / 15 m

X f / 6 m = 9,000 f / 15 m

Cross multiply

3,600 feet

5 0

3 years ago

Read 2 more answers

What is the inverse of the function f(x) = 4x + 8

Y_Kistochka [10]

Answer:

let f(x)= y

y = 4x+8

x= 4y + 8

4y = x - 8

y = (x - 8)/4

Hope this helps.

7 0

3 years ago

Read 2 more answers

This is my problem. I need help

koban [17]

Answer:

1: -3

2: She gives him $3 per week

3: 18

4: How much money she initially borrowed

5: y = -3x + 18

7 0

3 years ago

Use f(x) = 1/2 x and f -1(x) = 2x to solve the problems. f(2) = 1 f−1(1) = 2 f−1(f(2)) = 2 f−1(−2) = f(−4) = f(f−1(−2)) =

vampirchik [111]

Answer:

In this problem, we are given the following functions:

$f(x)=\frac{1}{2}x$

and its inverse function:

$f^{-1}(x)=2x$

First of all, we want to calculate $f(2)$ . This can be obtained by substituting

x = 2

into f(x). Doing so, we find:

$f(2)=\frac{1}{2}\cdot 2 = 1$

Then we want to calculate $f^{-1}(1)$ . We can do it by substituting

x = 1

into $f^{-1}(x)$ . Doing so,

$f^{-1}(1)=2\cdot 1 = 2$

Then we want to calculate $f^{-1}(f(2))$ , which can be found by calculating f(2) and then using it as input for $f^{-1}(x).$ We know that

f(2) = 1

Therefore,

$f^{-1}(f(2))=f^{-1}(1)=2$

Then we want to calculate $f^{-1}(-2)$ , which can be calculated by plugging

x = -2

into $f^{-1}(x)$ . Doing so,

$f^{-1}(-2)=2\cdot (-2)=-4$

Then we want to calculate $f(-4)$ ; by substituting

x = 4

into f(x), we find

$f(-4)=\frac{1}{2}\cdot (-4)=-2$

Finally, we want to find $f(f^{-1}(-2))$

We know already that

$f^{-1}(-2)=-4$

So we have:

$f(f^{-1}(-2))=f(-4)=-2$

7 0

3 years ago

Read 2 more answers