A shopper pays $22.05 for a $21 book of piano music after sales tax is added. What is the sales tax percentage?

= 5%

Step-by-step explanation:

sold price           =   22.05

marked price     =    21.00

sales tax             =    1.05

%sales tax =  sales tax x 100

                       marked price

%sales tax  =  1.05 x 100   = 105   = 5%

                           21.00           21          

remember the sales tax was added to the marked price to form the new price.

the percentage of the sales tax will therefore be determined on the marked price.

8

step-by-step explanation:

5x + 3y = - 4

step-by-step explanation:

the equation of a line in standard form is

ax + by = c ( a is a positive integer and b, c are integers )

express the line first of all in slope- intercept form

y = mx + c ( m is the slope and c the y-intercept )

to calculate m use the gradient formula

m = ( y₂ - y₁ ) / ( x₂ - x₁ )

with (x₁, y₁ ) = (7, - 3) and (x₂, y₂ ) = (4, - 8)

m = = -

y = - x + c ← is the partial equation

to find c substitute either of the 2 points into the partial equation

using (4, - 8 ), then

- 8 = - + c ⇒ c = -

y = - x - ← in slope-intercept form

multiply all terms by 3 to eliminate the fractions

3y = - 5x - 4 ( add 5x to both sides )

5x + 3y = - 4 ← in standard form