Two thirds X: two fifths = fifteen sixteenth: eight ninths

Two thirds X: two fifths = fifteen sixteenth: eight ninths

8/9*2x/3=2/5*15/16
16x/27=3/8
x=3/8÷16/27
X = 81 / 128

We know that P = 2 / 15 m - 2 / 9, q = m square - 8 / 15 m, compare the size of P, Q

∵q-p=m²-8/15m-2/15m+2/9
=m²-2/3m+1/9+1/9
=(m-1/3)²+1/9>0
∴q-p>0
∴p-q

How to open brackets? For example: three fifths - (two fifths + two fifths) and eight ninths - (eight ninths - four fifths + one fifths)

If it is a negative sign, the one in the bracket will change into a sign (positive to negative, negative to positive)