Work out the percentage change-decrease £77 by 70%

£ 23.10

Step-by-step explanation:

100% - 70%

= 30%

If 100% = £ 77

What about 30%

30% × £ 77 ÷ 100%

= £2310 ÷ 100

= £ 23.10

Part a : Slope is 40 and it interpret the rate of increase of balance in dollars in the account per day.

Part b :  y - 720 = 40(x - 3) ... Point-slope form. 40x - y +600 = 0 ... Standard form. g(x) = 40x + 600 ... Slope-intercept form.

Part c : $880

Step-by-step explanation:

The table of values represents a linear function g(x), where x is the number of days that have passed and g(x) is the balance in the bank account:

x  g(x)

0 $600

3 $720

6 $840

Part a : Therefore, the slope of the function will be and it interprets the rate of increase of balance in dollars in the account per day.

Part b : If we denote g(x) = y, then the equation that models the table will be

⇒ y - 720 = 40(x - 3) (1) Point-slope form.

⇒ 40x - y +600 = 0 (2) Standard form.

⇒ y = 40x + 600

⇒ g(x) = 40x + 600 (3) Slope-intercept form.

Part c : From equation (3), the balance in the account after 7 days will be

g(7) = 40(7) + 600 = 280 + 600 = 880 dollars. (Answer)