Answer:
4a. 7 phones on phone plan
4b. 10 phones
Other Problem: a = dy + cd
Step-by-step explanation:
4a.
1. First make equation: y = 15x+50
2. Plug in Number
155 = 15x + 50
-50 -50
105 = 15x
15 15
x = 7
4b.
1. Make Equation: 200 greater than or equal to 15x + 50
2. Solve
200 greater than or equal to 15x + 50
-50 -50
150 greater than or equal to 15x
15 15
x = 10
Second Question
y = a/d - c
Step 1: Move C to other side
y = a/d - c
+c +C
y+c = a/d
Step 2: Isolate A (Multiply all by d)
(multipy d to y and c) (d) y+c = a/d (d) (multiply by d to isolate a)
a = dy + cd
