Question 1179466
b) 

{{{m-2m^2 =-120}}}

 {{{m}}}={{{10}}},{{{8}}},{{{1}}},{{{-2}}},{{{ 7.5}}}


check {{{m=10}}}

{{{10-2*10^2 =-120}}}

{{{10-200=-120}}}

{{{-190<>-120}}}->{{{m=10}}}is {{{not}}} solution



check {{{m=8}}}

{{{8-2*8^2 =-120}}}

{{{8-128=-120}}}

{{{highlight(-120=-120)}}}->{{{highlight(m=8)}}}  {{{highlight(is)}}} solution


check {{{m=1}}}

{{{1-2*1^2 =-120}}}

{{{1-2 =-120}}}

{{{-1<>-120}}}->{{{m=1}}}is {{{not}}} solution



check {{{m=-2}}}

{{{-2-2*(-2)^2 =-120}}}

{{{-2-8 =-120}}}

{{{-10<>-120}}}->{{{m=-2}}}is {{{not}}} solution



check {{{m=7.5}}}

{{{7.5-2*(7.5)^2 =-120}}}

{{{7.5-8 =-120}}}

{{{-0.5<>-120}}}->{{{m=7.5}}}is {{{not}}} solution