Answer is 48.
The way to solve this is on the left hand side of the triangle you would add the top and the very left number. In this case 6+2=8. Next you will multiply the number you just found from the two left numbers to the very right number. So now you have 8x6=48.
Just use your problem solving skills with guessing and checking. For example in the first one you will know that 8x4 is already too big of a number so you need to make a smaller number. Then try adding and subtracting.