3MN²/(M²-N²) или (M²-N²)/3MN²
2
XY/4(X²-Y) или 4(X²-Y)/XY
3
(A-B)/(-AB) или -AB/(A-B)
30/10=x/4
30*4=10x
-10x=-120:(-10)
x=12
x-1/2,4=15/3,4
(x-1)*3,4=15*2,4
3,4x-3,4=36
3,4x=36+3,4
3,4x=39,4:3,4
x=394/34
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