Question 907460
one  investment all 3 rates
0.05*7000+0.09(x)=0.07(7000+x)
Multiply out.
350+0.09(x)=490+0.07x
combine like terms
0.02x=140
isolate x
x=140/0.02
Divide
x=7000
check
0.05*7000+0.09(x)=0.07(7000+x)
350+0.09*7000=0.07(7000+7000)
350+630=0.07(14000)
980=980
ok