#21-24 need help with

117

Step-by-step explanation:

1×2^6 + 1×2^5 + 1×2^4 + 0×2^3 + 1×2^2 + 0×2^1 + 1×2^0

1×64+1×32+1×16+0×8+1×4+0×2+1×1

=64+32+16+0+4+0+1

=117

1) is right

step-by-step explanation:

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!