Hannah and heather are sisters. hannah's age is four less than twice heather's age. the sum of their ages is 30. which system of equations can be used to determine hannah's age, x, and heather's age, y?

a.
x + 30 = y
x = 2 - 4y

b.
x + y = 30
x - 2y = 4

c.
x + y = 30
x = 2y - 4

d.
x + y = 4
y = 30 - 2x

What are “like terms”? why can we only add like terms?

The average number of vehicles waiting in line to enter a parking lot can be modeled by the function f left parenthesis x right x squared over 2 left parenthesis 1 minus x right parenthesis endfraction , where x is a number between 0 and 1 known as the traffic intensity. find the rate of change of the number of vehicles waiting with respect to the traffic intensity for the intensities (a) xequals0.3 and (b) xequals0.6.

Daniel expanded the expression as shown below -2(-8x-4y+3/4)=-10x-8y-11/4 what errors did he make? check all that apply