Answer: A)

Step-by-step explanation: To solve this problem we need to express the given equation in different ways (for example, isolating b or r) and compare it with the given options, to see which one of them is correct:
given equation:
4b+6r=20
isolating r:
6r=20-4b

simplifying by 2:

isolating b:
4b=20-6r

simplifying by2:

dividing each term by 2:
