Keiko's Coffee Shop makes a blend that is a mixture of two types of coffee. Type A coffee cost Keiko $4.15 per pound, and type B coffee costs $5.25 per pound. This month's blend used four times as many pounds of type B coffee as type A, for a total cost of $980.85. How many pounds of type A coffee were used?

39 pounds of type A coffee were used.

Step-by-step explanation:

Let,

x be the pounds of type A coffee used

y be the pounds of type B coffee used

According to given statement;

4.15x+5.25y=980.85      Eqn 1

y = 4x    Eqn 2

Putting y=4x in Eqn 1

4.15x+5.25(4x) = 980.85

4.15x+ 21x = 980.85

25.15x = 980.85

Dividing both sides by 25.15

Hence,

39 pounds of type A coffee were used.

225x²+4=0

225x²=0-4

225x²=-4

x²=-4/225

x=±√-4/225