Step-by-step explanation:
in a rhombus (not rumbus !) all sides are equally long.
that means
7x - 4 = 3x + 12
4x = 8
x = 2
F(x) = 20x+300
you sub in the x values (120 hours and 100 hours) for each equation
the only one they both work for is the last one
f(x) = 20x + 300
f(100) = (20 * 100) + 300 = 2000 + 300 = 2300
f(120) = (20 * 120) + 300 = 2400 + 300 = 2700
Answer:
28j + 21
Step-by-step explanation:
combine like terms
7(2j+ 3+ 2j)
7(4j+3)
Distribute
7(4j + 3)
=
28j + 21