Answer:
y = - x + 9
Step-by-step explanation:
the equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
calculate m using the slope formula
m =
with (x₁, y₁ ) = (0, 9) and (x₂, y₂ ) = (9, 0) ← 2 points on the line
m = =
= - 1
the line crosses the y- axis at (0, 9 ) ⇒ c = 9
y = - x + 9 ← equation of line
Answer:
Step-by-step explanation:
Solution is given below in attachment
Suppose that Carol has x 10p coins in her purse. Since she has three times as many 20p coins as 10p coins, then she has 3x 20p coins in her purse.
x coins of 10p value $0.10x and 3x coins of 20p value $0.60x.
In total this amount of money is $(0.10x+0.60x)=$0.70x that is exactly $4.20. Thus, you get the equation
0.70x=4.20.
Solve it:
Carol has 6 coins of 10p and 3·6=18 coins of 20p.