We have [tex] \left \{ {{2a=8} \atop {a+b=2}} \right. [/tex] First we are taking first equation, and we are solving it 2a=8 /:2 divide both sides by 2 a=4 Now we can backsubstitute a=4 a+b=2 4+b=2 /-4 (subtract 4 both sides) 4+-4+b=2-4 b=-2 The final answer is [tex] \left \{ {{a=4} \atop {b=-2}} \right. [/tex]
