Question

tìm x

a) -x/4=-9/x       b) x/4=18/x+1

Answer 1

a, -x/4 = -9/x

=> -x.x = 4.(-9)

=> -x² = -36

=> x² = 36

=> x = + 4

vậy_

b, x/4 = 18/x + 1

=> x(x + 1) = 4.18

=> x(x + 1) = 72

=> x(x + 1) = 8.9

=> x = 8

vậy_

Answer 2

a)\(\frac{-x}{4}=\frac{-9}{x}\)

\(\Rightarrow-x\times x=-9\times4\)

\(\Rightarrow-x^2=-36\)

\(\Rightarrow x=6\)