Question

by what rational number should -3/4 be multiplied in order to get -21/64

Answer 1

$\frac{ - 3}{4} \times x = \frac{ - 21}{64}$
$x = \frac{ - 21}{64} \times \frac{ - 4}{3} = \frac{ 7}{16}$

Answer 2

Lets assume the number to be x
According To Question
-3/4×x=-21/64
Cross Multiply
64×-3×x=-21×4
-192x=-84
x=-84/-192
x=7/16 answer