Question 224763
x/3 = 4/ x+1 cross multiply
x(x+1)=3*4
x^2+x=12
x^2-x-12=0
(x-4)(x+3)=0
x-4=0
x=4 ans.
x+3=0
x=-3 ans.
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-3/x = x/-3 cross multiply.
x^2=-3*-3
x^2=9 
x=sqrt9 
x=+-3 ans.