as i'm reading a paper a paper "An Underdetermined Linear System for GPS" By Dan Kalman
and solving an equation ,and as i'm not good in math i missed there ,in factoring of the following equation: $t=-0.047^2\cdot2.4^2+0.047^2\cdot19.9^2$ how can i facor the similar terms ,i mean simplify the equation
is this equation equals to,
$t=-0.047^2(2.4^2+19.9^2)$ or $t=0.047^2(19.9^2-2.4^2)$
which one is correct and why.