How do you simplify (8.39 xx 10^-7)(4.53 xx 10^9)(8.39×107)(4.53×109)?

4 Answers
Mar 19, 2018

(8.39 xx 10^-7)xx(4.53 xx10^9)(8.39×107)×(4.53×109)

=3.80067 xx 10^3=3.80067×103

Explanation:

Consider the product of " "3x^-7 xx 7x^9 3x7×7x9

rarr multiply the numbers and add the indices of like bases.

= 21 x^(-7+9)=21x7+9

=21x^2=21x2

Exactly the same happens when you are multiplying numbers in scientific notation.

rarr multiply the numbers and add the indices of like bases.

(8.39 xx 10^-7)xx(4.53 xx10^9)(8.39×107)×(4.53×109)

38.0067 xx 10^(-7+9)38.0067×107+9

color(blue)(38).0067 xx 10^2" "larr38.0067×102 not in scientific notation.

=3.80067 xx 10^3=3.80067×103

Mar 19, 2018

See a solution process below:

Explanation:

First, rewrite the expression as:

(8.39 xx 4.53) xx (10^-7 xx 10^9) =>(8.39×4.53)×(107×109)

38.0067 xx (10^-7 xx 10^9)38.0067×(107×109)

Now, we can use this rule for exponents to simplify the 10s terms:

x^color(red)(a) xx x^color(blue)(b) = x^(color(red)(a) + color(blue)(b))xa×xb=xa+b

38.0067 xx (10^color(red)(-7) xx 10^color(blue)(9)) =>38.0067×(107×109)

38.0067 xx 10^(color(red)(-7)+color(blue)(9)) =>38.0067×107+9

38.0067 xx 10^238.0067×102

To write this in scientific notation we need to move the decimal point one place to the left so we need to add 11 to the 10s exponent:

3.80067 xx 10^(2+1) =>3.80067×102+1

3.80067 xx 10^33.80067×103

Or, in standard terms:

3800.673800.67

Mar 19, 2018

By first combining the exponential terms, you can simplify the problem significantly, and get 3.80067xx10^33.80067×103 as the result.

Explanation:

The first thing to do is rewrite the function so all of the multiplication is outside of parentheses, and the exponents are grouped together:

(8.39xx10^(-7))(4.53xx10^9)=8.39xx4.53xx10^9xx10^(-7)(8.39×107)(4.53×109)=8.39×4.53×109×107

Next, lets multiply the constants together, and use scientific notation to describe the result:

8.39*4.53=38.0067=3.80067xx10^18.394.53=38.0067=3.80067×101

Re-writing the equation:

3.80067xx10^1xx10^9xx1010^(-7)3.80067×101×109×10107

Finally, we combine the notation terms. When you multiply two exponential numbers with the same base, it is the same as adding the exponents together, like so:

x^nxx x^z=x^(n+z)xn×xz=xn+z

using that principle:

10^1xx10^9xx10^(-7)=10^(1+9-7)=10^3101×109×107=101+97=103

Now, lets re-write the equation one last time with all of our simplification:

color(red)(3.80067xx10^3)3.80067×103

Mar 19, 2018

Suppose the idea of decimals is giving you a problem.

3.80067xx10^33.80067×103

Explanation:

color(blue)("Consider: "8.39)Consider: 8.39
this is the same as 839xx1/100 = 839xx10^(-2)839×1100=839×102

So we have:

[ 8.39 ]xx10^(-7) ->[839xx10^(-2)]xx10^(-7) = 839xx10^(-9)[8.39]×107[839×102]×107=839×109
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

color(blue)("Consider: "4.53)Consider: 4.53

Using the same argument as above we have:

[453xx10^(-2)]xx10^9= 453xx10^7[453×102]×109=453×107
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
color(blue)("Putting it all together")Putting it all together

(839xx10^(-9))(453xx10^7) =839xx453xx10^7/10^9(839×109)(453×107)=839×453×107109

380067xx1/10^2380067×1102
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

380067xx1/10xx1/10 = 3800.67380067×110×110=3800.67

3800.67" is the same as "380.067xx103800.67 is the same as 380.067×10
3800.67" is the same as "38.0067xx10xx103800.67 is the same as 38.0067×10×10
3800.67" is the same as "3.80067xx10xx10xx103800.67 is the same as 3.80067×10×10×10

So in Scientific notation we have: 3.80067xx10^33.80067×103