51. Prove that if the slopes of two lines have product -1, then the lines are perpendicular. Use parts (a)–(c) to write a coordinate proof. a. First, argue that neither line can be horizontal or vertical. b. Then, tell why the lines must intersect. (Hint: Use indirect reasoning.) c. Place the lines in the coordinate plane. Choose a point on /1 and find a related point on /2. Complete the proof.

idk

step-by-step explanation:

idk

boxplot

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!