Answer:
-7
Step-by-step explanation:
-20 × -7 = 140
140 × -7 = -980
Answer:
False
Step-by-step explanation:
i did this question and got it right
Number of weekend minutes used: x
Number of weekday minutes used: y
This month Nick was billed for 643 minutes:
(1) x+y=643
The charge for these minutes was $35.44
Telephone company charges $0.04 per minute for weekend calls (x)
and $0.08 per minute for calls made on weekdays (y)
(2) 0.04x+0.08y=35.44
We have a system of 2 equations and 2 unkowns:
(1) x+y=643
(2) 0.04x+0.08y=35.44
Using the method of substitution
Isolating x from the first equation:
(1) x+y-y=643-y
(3) x=643-y
Replacing x by 643-y in the second equation
(2) 0.04x+0.08y=35.44
0.04(643-y)+0.08y=35.44
25.72-0.04y+0.08y=35.44
0.04y+25.72=35.44
Solving for y:
0.04y+25.72-25.72=35.44-25.72
0.04y=9.72
Dividing both sides of the equation by 0.04:
0.04y/0.04=9.72/0.04
y=243
Replacing y by 243 in the equation (3)
(3) x=643-y
x=643-243
x=400
Answers:
The number of weekends minutes used was 400
The number of weekdays minutes used was 243
It’s 39 -180 because they are completray
Answer:
170°
Step-by-step explanation:
Let a be the distance from Los Angeles to Chicago = 1744 miles, b be the distance from Chicago to New York = 714 miles and c be the distance from New York to Los Angeles = 2451 miles.
A is the angle opposite to side a, B is the angle opposite to side b and C is the angle opposite to side c.
Therefore the angle at Chicago is C.
From cosine rule:
c² = a² + b² - 2ab × cos (C)
2ab × cos (C) = a² + b² - c²
cos (C) = (a² + b² - c²) / 2ab
Substituting:
cos (C) = (1744² + 714² - 2451²) / 2×1744×741
cos (C) = -0.986
C = cos⁻¹ (- 0.986) = 170°
