She earns \$20$20dollar sign, 20 per hour as a carpenter and \$25$25dollar sign, 25 per hour as a blacksmith. Last week, Giselle worked both jobs for a total of 303030 hours, and earned a total of \$690$690dollar sign, 690.

Step-by-step explanation:

Question wants to know the number of hours se worked at each.

This is a simultaneous equation problem.

Assume the carpenter job is x and the blacksmith is y.

x + y = 30

20x + 25y = 690

Substitution:

x + y = 30

y = 30 - x

20x + 25y = 690

20x + 25(30 - x) = 690

20x + 750 - 25x = 690

-5x = 690 - 750

-5x = -60

x = -60/-5

= 12 hours for carpentry

y = 30 - x

= 30 - 12

= 18 hours for blacksmithing

question 1 is 8, question 2 is 9, question 3 is 24

step-by-step explanation:

now, the numbers they give you at the top are the key. from there, you just have to plug and chug! let's try 1, 2, and 3!

key: a=3, b=5, c=6

1. a+5

remember, a=3, so we plug that in to get 3+5=8

2. 15-c

c=6, so we plug that in to get 15-6=9

3. 4b

b=6, so we plug it in to get 4*6=24

time to try the rest on your own! if you put the answers below in a comment, i'll check them for you!