How would I work out a problem like this?? (ratios and proportions)

Question

I'm a little rusty on ratios and proportions because I haven't done them in a while.
My problem is #(x-1)/8=(x+2)/10#

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Answer 1 · 2018-07-10T07:57:58

#x=13#

By cross multiplication we get
#10(x-1)=8(x+2)#
dividing by #2#

#5(x-1)=4(x+2)#
expanding

#5x-5=4x+8#
adding #5# and subtracting #4x#

#x=13#