X + 2y - 3z = 11
2x + y - 2z = 9
4x + 3y + z = 16

X + 2y + -2y + -3z = 11 + -2y

2y + -2y = 0

X + 0 + -3z = 11 + -2y

X + -3z = 11 + -2y

X + -3z + 3z = 11 + -2y + 3z

-3z + 3z = 0

X + 0 = 11 + -2y + 3z

X = 11 + -2y + 3z

2)2x + -1y + y + 2z = 9 + y

-1y + y = 0

2x + 0 + 2z = 9 + y

2x + 2z = 9 + y

2x + 2z + -2z = 9 + y + -2z

2z + -2z = 0

2x + 0 = 9 + y + -2z

2x = 9 + y + -2z

x = 4.5 + 0.5y + -1z

3)

3

step-by-step explanation:

in standard form:

a= dictionaries

b= maps

you have to buy 3 dictionaries, so put a 3 next to the a (dictionaries) so that you can multiply them by each other.

a3+b= 60 (the amount of money you have)

we already know the cost of a=15 so replace a with $15

($15 x 3)+b=60

multiply 15 and 3 to get $45 and replace it with $45

45+b=60

and then replace b with 15 to get the total:

45+15=60

that means you have $15 left after buying 3 dictionaries.

15 divided by the cost of a map ($5) equals 3.

so you can buy 3 maps.

sorry if it was confusing!