Answer:
D.
Step-by-step explanation:
In order to eliminate, the numbers must eliminate. If the second equation is multiplied by 3, then the 3 and the -3 can be eliminated. Since it is multiple choice, we can plug in x = 12 and y = 10 to see if they are correct. 12 + 30 = 42 and 24 - 10 = 14, so D is correct.
Answer: e. 
Step-by-step explanation:
1. You have the following expression given in the problem:

2. To solve the exercise and find an equal expression, you must simplify that expression. Apply the Distributive property. Multiply the terms inside the parentheses by
. Then, you obtain:

Answer:
B. 840
Step-by-step explanation:
21 is 70% of 30 and 70% of 1,200 is 840.
H(1) = 4
h(1)= 5 x 1 -1
=5-1
=4
hope that helps <3