The two consecutive positive integers has a product of 272? What are the 4 integers?
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#(-17,-16)# and #(16,17)#
Let a be the smaller of the two integers and let a+1 be the bigger of the two integers:
#(a)(a+1) = 272#, easiest way to solve this is to take the square root of 272 and round down:
#sqrt(272) = \pm16...#
16*17 = 272
Thus, the integers are -17,-16 and 16,17
If we multiply two consecutive numbers, #n and n+1#
we get #n^2+n#. That is we square a number and add one more on.
#16^2=256#
256+16=272
So our two numbers are 16 and 17
#color(blue)("A sort of cheat way")#
The two number are very close to each other so lets 'fudge' it
#sqrt(272) = 16.49...# so the first number is close to 16
Test #16xx17=272 color(red)(larr"First guess gets the prize!")#
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#color(blue)("The systematic way")#
Let the first value be #n# then the next value is #n+1#
The product is #n(n+1)=272#
#n^2+n-272=0#
Compare to: #ax^2+bx+c=0color(white)("ddd") -> color(white)("ddd") x=(-b+-sqrt(b^2-4ac))/(2a)#
In this case #x->n; color(white)("d")a=1; color(white)("d")b=1 and c=-272#
#n=(-1+-sqrt(1-4(1)(-272)))/(2(1))#
#n=-1/2+-sqrt(1089)/2#
#n=-1/2+-33/2# The negative is not logical so discard it
#n=-1/2+33/2 = 16#
The first number is 16 the second is 17