Y is such that 4y - 7 ≤ 3y and 3y ≤ 5y + 8. A. What range of values of y satisfies both inequalities?

B. Hence express 4y - 7 ≤ 3y ≤ 5y + 8 in the form a ≤ y ≤ b, where a and b are both integers.

-4 ≤ y ≤ 7

Step-by-step explanation:

Inequalities

Solve the system of inequalities:

4y - 7 ≤ 3y       [1]

3y ≤ 5y + 8       [2]

A.

Subtracting 3y to [1]:

y - 7 ≤ 0

Adding 7:

y ≤ 7

Subtracting 5y to [2]:

-2y ≤ 8

Dividing by -2 (and flipping the sign):

y ≥ -4

The solution of the system is all the values of y greater or equal to -4 and less or equal to 7.

B.

The solution can be expressed as:

-4 ≤ y ≤ 7

answer: c, the green line

step-by-step explanation:

there is no black line, eliminate b.

simple interest implies periodic payments, but the red line shows no payments, eliminate d.

simple interest has equal payments. if paid say every day, the graph is about a straight line (actually a stairstep).

the yellow line is not straight, eliminate a.

check: the green line is straight, answer is c.

simple interest with positive interest rate gives a straight line sloping up to the right. green line:

g(t) = $100 + ($200-$100) ÷ (20 years) × (t years)

= $100 + (4%/year) × ($100)(t years)

incidentally, the yellow line curving upward represents continuously compounded interest

y = $100 × 2^(t years / (14 assuming the yellow line hits $200 at 14 years. 2^0 is 1, so y(0) = $100; 2^(14/14) is 2, so y(14) = $200.