Hello,
Let's calculate the radius:
r²=5²+7²=74
The circle's equation is (x+5)²+(y+7)²=74
Answer C
I feel it should be 30 because x represents the number of lessons, and 30 is multiplied by that.
If you're simplifying the expression, your answer would be 12r - 54s + 18t.
Answer:
height = 12 cm
base length = 4 cm
Step-by-step explanation:
area of a triangle
base length × height / 2
x = height
y = base length
x = y + 8
24 = y × (y + 8) / 2
48 = y × (y + 8) = y² + 8y
squared equation
y² + 8y - 48 = 0
solution
y = (-b ± sqrt(b² - 4ac))/(2a)
a = 1
b = 8
c = -48
y = (-8 ± sqrt(64 - 4×-48))/2 = (-8 ± sqrt(64 + 192))/2 =
= (-8 ± sqrt(256))/2 = (-8 ± 16)/2 = -4 ± 8
y1 = -4 + 8 = 4 cm
y2 = -4 - 8 = -12
but a negative base length did not make any sense, so only y = 4 remains.
x = y + 8 = 4 + 8 = 12 cm
