Perfect square is
a²+2ab+b²
so just take the square root of the end ones and add then double to get middle term
A.
m+10=10m, doubled is 20m
nope
B.
m+5=5m, doubled is 10m, yep
C.
m+2√15=fancy thing that won't get to 36m
D.
m+12=12m, doubled is 24m, yep
B and D
Answer:
$ 2,600 was invested at 4% and $ 3,600 was invested at 9%.
Step-by-step explanation:
Given that in investing $ 6,200 of a couple's money, a financial planner put some of it into a savings account paying 4% annual simple interest, and the rest was invested in a riskier mini-mall development plan paying 9% annual simple interest, and the combined interest earned for the first year was $ 428, to determine how much money was invested at each rate, the following calculation must be performed:
3000 x 0.04 + 3200 x 0.09 = 408
2500 x 0.04 + 3700 x 0.09 = 433
2600 x 0.04 + 3600 x 0.09 = 428
Therefore, $ 2,600 was invested at 4% and $ 3,600 was invested at 9%.
