Solve this system of equations using substitution.

a + b + c = 180

b = 3a

c = 5a

What is substitution in algebra

If you invest $20,000 in a mutual fund averaging 10% compounded monthly, how long will it take to reach $1 million?

It costs Charlie's Car Repair Shop $27 to change the oil. The shop charges their customers $40 for an oil change. What is the percent of markup in the cost of an oil change?

Dallison cooked a 5-pound roast for supper. What is estimated mass in grams? step by step solution?

Least common factor of 15 and 20

A shopper buys a 12 - pound bag of oranges for $18.75. What is the unit price?

Harry kept a record of how far he ran each day last week Distance (in miles) Monday 4.5 Tuesday 3.9 Wednesday 4.25 Thursday 3.75 Friday 4.2 On which day did Harry run the greatest number of miles?

Matthew collects purple and red marbles. he has 320 marbles and 65% of them are purple. How many red marbles does he have?

Multiply the complex numbers. (5+1i) (-3+2i)

Joe owns and apple orchard with 20 apple trees. Each year he will plant 7 more. Write and explicit formula for the number of apple trees in the orchard.