Please help! provide thorough explanation and use elimination method!!

Multiply both sides of the second equation by 100 to get rid of the decimals:

0.05n + 0.10d = 1.50

==>  5n + 10d = 150

Multiply both sides of the first equation by -5:

n + d = 21

==>  -5n - 5d = -105

Add the two equations together:

(5n + 10d) + (-5n - 5d) = 150 + (-105)

Notice that the terms containing n get eliminated and we can solve for d :

(5n - 5n) + (10d - 5d) = 150 - 105

5d = 45

d = 45/5 = 9

Plug this into either original equation to solve for n. Doing this with the first equation is easiest:

n + 9 = 21

n = 21 - 9 = 12

So Donna used 12 nickels and 9 dimes.

step-by-step explanation:

the triangles are similar. therefore the corresponding sides are in proportion:

              cross multiply

            divide both sides by 32

(a) {a₁, a₁r, a₁r², … a₁rⁿ⁻¹, …}

(b) $59 398

step-by-step explanation:

(a) the annual sequence of profits

aₙ = a₁rⁿ⁻¹

the model for the sequence of profits is {a₁, a₁r, a₁r², … a₁rⁿ⁻¹, …} .

(b) profit after 15 yr

  a₁ = $ 30 000

  r = 1.05

a₁₅ = 30 000 × 1.05¹⁴

a₁₅ = 30 000 × 1.979 93

a₁₅ = $59 398

the profit in year 15 will be $59 398.