Me podrian ayudar con que es 3×-y=7 4×-2y=28
you want the sum of the distances to equal 1900 miles.
they are travelling in opposite directions and therefore the distances will add.
let the number of hours = t
d = r*t
635*t + 325*t = 1900 combine the right
960*t = 1900 divide by 960
960t/960 = 1900/960
t = 1.98 hours or 1 hour and 58.8 minutes or 1 hour 58 minutes 48 seconds.
without choices, i don't know which answer you want. perhaps even 2 hours is (rounded) close enough
option d. 9(5x+4)(5x-4)
we are given an expression 225x² - 144 and we have to write it in factored form
225x² - 144
taking 9 common in the above expression
9(25x² - 16)
25x² can be written as (5x)² and 16 as 4²
9((5x)² - 4²)
(5x)² - 4² = (5x+4)(5x-4)
using formula a² - b² = (a+b)(a-b)
9(5x+4)(5x-4) is the solution