Tara worked on her science fair project for 4 hours every day for 4 days. Which is the best estimate of the number of hours Tara spent on her science project?
A. 20
B. 16
C. 25
D. 30
What is the answer?

What are the values of each variable in the diagram below?

The equation line of cd is y=-2x-2. write an equation of a line parallels to line cd in slope-intercept form that contains point (4,5)

Which of these statements is correct? the system of linear equations 6x - 5y = 8 and 12x - 10y = 16 has no solution. the system of linear equations 7x + 2y = 6 and 14x + 4y = 16 has an infinite number of solutions. the system of linear equations 8x - 3y = 10 and 16x - 6y = 22 has no solution. the system of linear equations 9x + 6y = 14 and 18x + 12y = 26 has an infinite number of solutions.