Final answer:
To solve the equation 4a=2b-7 and find the value of b when a=3, isolate b on one side of the equation by adding 7 to both sides, dividing both sides by 2, and simplifying the expression. The value of b when a=3 is 9.
Step-by-step explanation:
To solve for b in the equation 4a=2b-7, we need to isolate b on one side of the equation. First, let's simplify the equation by adding 7 to both sides: 4a + 7 = 2b. Next, divide both sides by 2: (4a + 7) / 2 = b. Finally, simplify the expression: b = 2a + 3.
To find the value of b when a = 3, substitute 3 in place of a in the equation: b = 2(3) + 3. Simplify the expression: b = 6 + 3 = 9. Therefore, when a = 3, the value of b is 9.