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.