Answer:
The solution is x = 0, y = -2.
Step-by-step explanation:
5x - 3y = 6
6x - 5y = 10
If we multiply the first equation by 5 and the second by - 3 we get:
25x - 15y = 30
-18x + 15y = -30 Adding these 2 equations eliminates y, we get:
7x + 0 = 0
x = 0.
Substituting x = 0 in the first equation:
5(0) - 3y = 6
y = 6/-3 = -2.
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: Reflection
Step-by-step explanation:
