8.4.9 On or off the line & Practice Problems

Number of quarters → 15

Number of dimes → 2

Step-by-step explanation:

Let the number of dimes I have = y

And number of quarters = x

Since, I have amount in my pocket = $2

Therefore, 0.10y + 0.25x = 2

100(0.10y + 0.25x) = 100×2

25x + 10y = 200

5x + 2y = 40

2y = -5x + 40

y = -2.5x + 20 ---------(1)

Total number of coins in my pocket = 17

x + y = 17

y = -x + 17 ---------(2)  

By using a graphing calculator we can graph these two lines (As attached)

Solution of the given system of equations will be the point of intersection of these lines.

Solution → (2, 15)

Number of quarters → 15

Number of dimes → 2

2

step-by-step explanation:

7! = 7×6×5×4×3×2

3! = 3× 2

as 7! is multiple of 3! because 7! contains 3! that is 3× 2 as factor

so 7! /(3! ) = 7× 6× 5× 4

= 42 × 20

= 840

its b) 840✌✌✌

dhruv⭐