7x-9+3x+4 simplify by combining like terms

I have $1.00 in coins on my desk made up of nickels and dimes. I have 4 more dimes than nickels. How many nickels do I have?

If r = 25 cm and s = 7 cm, what is the length of t? A. 26 cm B. 23 cm C. 22 cm D. 24 cm

What is the value of x (2x+6) = 32

Jim goes to the store and buys 3 sodas for $1.29 each and a bag of chips for 1.59. What is Jim's subtotal?

Frank has four different credit cards, the balances and interest information of which are outlined in the table below. He would like to consolidate his credit cards to a single credit card with an APR of 18% and pay off the balance in 24 months.

Boat 1 leaves a dock headed due west at 8:00 AM traveling at a speed of 12 mph. At the same time a boat 2 leaves the dock headed due south traveling at a speed of 24 mph.

A Mathematics test was taken by 4 boys and 6 girls. The mean marks of the 10 students was 49. a) Calculate the total marks obtained by 10 students. b) If the mean marks of 6 girls was 51, calculate the mean marks of 4 boys.

Find an equation using absolute value that has the given solutions, a. two solutions, 22 and 22 b. two solutions, - 51 and 5 c. two solutions, - 9 and 39 d. one solution, 18

An object is launched from a platform. It's height is meters is modeled by: h (x) = - 5 (x+1) (x-9) where x represents the time in schools after the launch. How many seconds after launch will the object hit the ground

Each of the p children at a park receive 3 balloons. If the children receive at least 150 balloons in all, find the minimum number of children at the park.