Answer:
X=3, y=-6
Step-by-step explanation:
7x+4y=-3 equation 1
-7x-5y=9 equation 2
-y=6. Add above two equations
Y=-6
solve for x by inputting y value into either equation.
7x+4(-6)=-3
7x-24=-3
7x=21
x=3
check answer by inputting x and y values into either equation
-7x-5y=9
-7(3)-5(-6)=9
–21+30=9
9=9
Answer:
8,146 x 121
Step-by-step explanation:
This is a problem in which you need to measure your understading of "orders of magnitude."
If the estimated answer is 
that means that we are looking at a multiplication in the "order of" 
You need to look at the "orders of magnitude" of the things you're multiplying. In the first case, we have 
that would be "of the order of" 
times 
. So the whole multiplication would "of the order of" 
or near 
The correct answer, 8,146 x 121, is because it's "of the order of" times 
and the gives us the we need.
The answer is D. Because (18 x 10^6) + (5 x 10^4) = 18050000. And the answer to 1.805 x 10^7 also equals 18050000, if you do the math.
