Question

•Determine o valor de K para que as funções abaixo sejam decrescentes.

a)y=(k+3)x-9
b)y=(5k-25)x-7
c)y=(-3k+1/2)x+5
d)y=(-3/2-8k)x+2

Answer 1

A função é decrescente quando y = ax+b a<0

$a) \\ y=(k+3)x-9 \\ \\ k+3\ \textless \ 0 \\ \\ k\ \textless \ -3 \\ \\ \\ b) \\ y=(5k-25)x-7 \\ \\ 5k-25\ \textless \ 0 \\ \\ 5k\ \textless \ 25 \\ \\ k\ \textless \ 5 \\ \\ c) \\ (-3k+ \frac{1}{2} )x+5 \\ \\ -3k+ \frac{1}{2}\ \textless \ 0 \\ \\ -3k\ \textless \ - \frac{1}{2} \\ \\ k\ \textgreater \ \frac{1}{6} \\ \\ d) \\ (- \frac{3}{2} -8k)x+2 \\ \\ - \frac{3}{2}-8k\ \textless \ 0 \\ \\ -8k\ \textless \ \frac{3}{2} \\ \\ k\ \textgreater \ - \frac{3}{16}$