Answer:
y = -1/2 x
Step-by-step explanation:
Follow the directions "Complete the steps to write the equation of direct variation. Start with the equation of direct variation y = kx. Substitute in the given values for x and y to get . Solve for k to get . Write the direct variation equation with the value found for k."
y = kx substitute y = -4 and x = 8.
-4 = k*8
-4/8 = k
-1/2 = k
So the equation is y = -1/2(x).
Answer:
a) 1+2+3+4+...+396+397+398+399=79800
b) 1+2+3+4+...+546+547+548+549=150975
c) 2+4+6+8+...+72+74+76+78=1560
Step-by-step explanation:
We know that a summation formula for the first n natural numbers:
1+2+3+...+(n-2)+(n-1)+n=\frac{n(n+1)}{2}
We use the formula, we get
a) 1+2+3+4+...+396+397+398+399=\frac{399·(399+1)}{2}=\frac{399· 400}{2}=399· 200=79800
b) 1+2+3+4+...+546+547+548+549=\frac{549·(549+1)}{2}=\frac{549· 550}{2}=549· 275=150975
c)2+4+6+8+...+72+74+76+78=S / ( :2)
1+2+3+4+...+36+37+38+39=S/2
\frac{39·(39+1)}{2}=S/2
\frac{39·40}{2}=S/2
39·40=S
1560=S
Therefore, we get
2+4+6+8+...+72+74+76+78=1560
Answer: -10,-5,3,15
A,C,D,E
The next one is a= -5, b=1, c=-5, d=-12
The last one is 3 & 4
When we solve these equations x= 7.5 and y= 1.5.
(1 3/4) / (3/4) = x / 1.....1 3/4 miles to 3/4 hrs = x miles to 1 hr
cross multiply
(3/4)(x) = (7/4)(1)
3/4x = 7/4
x = 7/4 * 4/3
x = 28/12
x = 2 1/3 miles in 1 hr <==
