let's separate the 26000 into two pieces

1) x

2)26000-x

x will represent a certain value between 0 and 26000. Once you know x you can subtract it from 26000 to determine the other amount between 0 and 26000.

x(.05)+(26000-x)(.12)=1720

.05x+3120-.12x=1720

-.07x=-1400

x=20000

x equals 20000 and that value is the one invested at 5 percent while 26000-20000=6000 is the amount invested at 12 percent.

Chris J.

Marky mark I commented a answer and you never responded. Come on now marky it’s the same guy . Merry Christmas marky poo12/22/20