If a+b=7 and ab=30 find tha value of a³±b³

Question

If a+b=7 and ab=30 find the value a³+b³

Answer 1

1: a+b=7, so b=7-a . . . 2 ; ab=30 . . . a*(7-a)=30 . . . -a^2 +7a -30=0 . . . or a^2 -7a +30=0 . . . quadratik equashun giv roots= . . . 3.5 +-4.2130749i (komplex variabels) . . . b^2-4ac=-71 . . . mi ges is a=3.5+4.2...i & b=3.5-4.2....i . . . me leev it tu yu tu kube a & b . . .