To evaluate this, plug in the number 4 for the variable a and the number 5 for the variable 5.
6a + 3ab 6(4) + 3(4)(5)
To solve this multiply then add. Multiply from left to right and don't add until everything has been multiplied. Basically, 6(4) + 3(4)(5) = (6 • 4) + (3 • 4 • 5). 6 • 4 = 24 3 • 4 = 12 12 • 5 = 60
Now we have 24 + 60. Just add and you have your answer! 24 + 60 = 84
So when a is 4 and b is 5, <span>6a + 3ab is equal to 84.