Question 183477
Let {{{p}}}= kg of potatoes bought
Let {{{c}}}= kg of carrots bought
given:
(1) {{{c + p = 9}}}
(2) {{{.75c + .79p = 6.6}}}
This is 2 equations and 2 unknowns, so it's solvable
Multiply both sides of (1) by {{{.75}}} and 
subtract from (2)
(2) {{{.75c + .79p = 6.6}}}
(1) {{{-.75c - .75p = -6.75}}}
(3) {{{.04p = -.15}}}
There's a problem here, I end up with a negative
number for {{{p}}}. One or more of the numbers in
the problem is wrong- check it again, then
follow my method & you should do OK