We need a picture of the problem... then we can help you.
For this one you want to cancel out the x-terms.
Multiply top equation by -2
---> -2x -10y = 6
---> 2x +7y = 3
Add them together
---> -3y = 9
Solve for y ...
Hi, the answer is ;
Answer:
12 dimes and 27 nickels
Step-by-step explanation:
.05N + .1d = 2.55
N= 3d - 9
0.05 (3d-9) + 0.1d = 2.55
0.15d - 0.45 + 0.1d = 2.55
0.25d = 2.55 + 0.45
0.25d = 3
D = 12
N = 3 (12) - 9
N = 36 - 9
N = 27
The idea being, when you run a perpendicular line to the base, from the right-angle in a right-triangle, like in this case, what you end up with is, three similar triangles, a Large triangle containing the two smaller ones, a Medium triangle and a Small one, check the picture below.
since all three are similar, we can use the proportions on the corresponding sides, as you see in the picture, the base of the triangle then will just be x + y.
The formula required to answer this is:

where A is the amount of the principal P after n compounding periods per year at r interest rate (as a decimal fraction).
Plugging in the given values, we get:

Rounding to the nearest dollar, we get $662.00. Therefore a is the best answer choice.