18. Find the equation of the circle containing the points (-1.-1) and (3, 1) and with the centre on the line x-y + 10 = 0

x^{2} +2x+y^{2}+2y= 18

Step-by-step explanation:

equation of circle is:

using distance formula and substituting value,

solving,

r=

for equation of circle,

on solving,

on solving,

she was supposed to add the hours(38.5) and multiply the amount of money she earned(7.50) resulting in $288.75 .

correct me if i'm wrong and if it is i'm truly sorry.

step-by-step explanation:

the ratio of red paint to blue paint is always 9/7. that means that, whatever x's value, (4x+12)/(4x-4) has that same ratio. so, set up an equation and cross-multiply to solve for x:

9/7 = (4x+12)/(4x-4)

9(4x-4) = 7(4x+12)

36x - 36 = 28x + 84

8x - 36 = 84

8x = 120

x = 15