Answer:
380 + 6 + 14
Step-by-step explanation:
The sum of 386 and 14 is 386 + 14 = 400.
To find which stategy he used, we find the results of each sum, and it has to be 400.
380 + 6 + 14
380 + 6 + 14 = 386 + 14 = 400
So this is the strategy that he could have used.
380 + 14 + 14
380 + 14 + 14 = 394 + 14 = 408
Result different of 400, which means that this was not the strategy
386 + 10 + 4 + 14
386 + 10 + 4 + 14 = 386 + 14 + 14 = 408
Result different of 400, which means that this was not the strategy
386 + 14 + 80 + 6
386 + 14 + 80 + 6 = 400 + 86 = 486
Result different of 400, which means that this was not the strategy
Answer:
25(a-2)(a+2)
Step-by-step explanation:
25a^2 -100
We can factor out 25
25(a^2 -4)
a^2 -4 is the difference of squares a^2-b^2= (a-b)(a+b)
where a =a and b=2
a^2 -4 = (a-2)(a+2)
25a^2 -100 = 25(a-2)(a+2)
Answer:
46
Step-by-step explanation:
Adding the given numbers of columns on each side counts each corner column twice. Therefore, we must subtract 4 corner columns from the total.
2(8+17) -4
= 2(25) -4
= 50 -4
= 46
