2. The resting pulse rates were recorded for 16 boys in gym class
before they exercised. The line plot here shows the results.
X
X
X
Х
X
Х
X
Х
X
X
X
X
X
Х
X
X
79
80
81
82
83
84
85
a.
What is the range of the pulse rates?
b. How many boys had a pulse rate over 81?
c. How many boys had a pulse rate of 83?

hello from mrbilldoesmath!

answer:   (7x + 6y) ( 49x^2 - 42xy + 36y^2)

discussion:

in general, the factorization of a^3 + b^3 is

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

in our case note that 343 = 7^3 and 216 = 6^3 so the equation becomes:

343x^3 + 216y^3 = (7x)^3 + (6y)^3

if you think of a (above) as 7x and b as 6y the factorization becomes

343x^3 + 216y^3 =

((7x + 6y) (   (7x)^2 - 7x*6y + (6y)^2)   =

(7x + 6y) ( 49x^2 - 42xy + 36y^2)

you,

mrb

(a + b) (a^2 - a b + b^2)

=

x=0.8898305 is the answer to that equation

doubled

step-by-step explanation: