To find how long it would take him, one has to divide 400 by 160 and then multiply 5 by what that number is. You multiply 5 by the quotient because that is the number that would make it proportional. 400/160 x 5 is 12.5, meaning that the answer is 12.5 minutes, or A.

5 0

2 years ago

Solve by square rooting : 3(X+2)^2:8

dolphi86 [110]

The value of x is √8/3 - 2

Step by step explanation:

The given equation is

3(x+2)^2=8

To find x,

(x+2)²= 8/3

By taking square root on both sides

x+2= √8/3

x=√8/3 -2

x= -0.37

Thus the square root for the given value is -0.37

3 0

3 years ago

What is the justification for the first step in proving the formula for factoring the sum of cubes?

Anna11 [10]

Explanation:

The formula isnt correctly written, it should state:

$a^3+b^3 = (a+b)(a^2-ab+b^2)$

You have to start from $(a+b)(a^2-ab+b^2)$ and end in a³+b³. On your first step, you need to use the distributive property.

$(a+b)(a^2-ab+b^2) = a*(a^2-ab+b^2) + b*(a^2-ab+b^2)$

This is equal to

$a*a^2-a*(ab) + a*b^2 + b*a^2-b*(ab) + b*b^2 = a^3 - a^2b + ab^2 +ba^2 -b^2a +b^3$

Note that the second term, -a²b, is cancelled by the fourth term, ba², and the third term, ab², is cancelled by the fifht term, -b²a. Therefore, the final result is a³+b³, as we wanted to.

5 0

3 years ago