4. Danielle invested $2,300 in a savings account. After 9 years she had made $1,449 in interest. What was the interest rate for this account?

7% per year

Step-by-step explanation:

The formula for Simple Interest rate is given as:

r = (1/t)(A/P - 1)

Where:

t = time in years = 9 years

P = Initial amount invested = $2300

A = Total amount after t years

= Interest + Principal

= $2300 + $1449

= $3749

r = (1/9) × ($3749/$2300 - 1)

r = 0.07

Converting r decimal to R a percentage

R = 0.07 * 100 = 7%/year

f(x) has value 150 at x= 0

and 0 at x= 3

so d(f(x))/dt = slope = -150/3 = -50

the system of inequalities is

step-by-step explanation:

step 1

find the equation of the dashed line

we have the points

(0,0) and (3,1)

the line passes through the origin, so, is a direct variation

find the slope

the equation of the dashed line is

the solution of the inequality a s the shaded area above the dashed line

therefore

the equation of the inequality a is

step 2

find the equation of the solid line

we have the points

(4,0) and (0,4)

find the slope

the equation of the solid line is

the solution of the inequality b s the shaded area below the solid line

therefore

the equation of the inequality b is

step 3

the system of inequalities is