Answer:
x=7
Step-by-step explanation:
x-1
3x-5
______
4x-6
4x-6= 7x-27
-4x -4x
___________
-6= 3x-27
+27 +27
____________
21= 3x
divide both 21 and 3x by 3
= 
7 = x
x=7
Answer:
9
Step-by-step explanation:
3-(-6)=9
We calculate the speed by dividing the distance over time:
s = d/t
So the distance described in the problem is always the same, A to B and B to A.
But we are told that;
7 = d/t
7 = 2d/(t + 2)
that is, the first equation say that at speed 7 km/h a distance d is walked in a time t
the second equation say that at a average speed of 7 (that is 8 on one way and 6 in the other: 8 + 6 = 14, half of it), twice the distance is walked in a time equal to the first time plus 2 minutes.
So we have a system of linear equations, 2 of them with two unknowns, we can solve that:
7 = d/t
7 = 2d/(t + 2<span>)
</span>lets simplify them:
7t = d
7(t + 2) = 2d
7t = 2d - 14
we substitute the first in the second:
<span>7t = 2d - 14
</span><span>7t = d
</span>so:
d = 2d - 14
d = 14
so the distance between A and B is 14 km
Answer:
2 (x + 3)^2 - 2
Step-by-step explanation:
1. Factor the 2 out of the equation (don't forget about it - it will be used later). This gives you x^2 + 6x + 7
2. Subtract the 7 over. This gives you x^2 + 6x = -7
3. Take b (6), divide it by 2 (3), and square it (9). Then add that to both sides of the equation. This gives you x^2 + 6x + 9 = 2
4. Factor the left side of the equation. This gives you (x + 3)^2 = 2
5. Subtract the 2 over. This gives you (x + 3)^2 - 2
6. Remember that 2 we factored out of the equation earlier? Well that goes in front of the parentheses now, giving you the final answer of 2 (x + 3)^2 -2
6. 1,750 mg in a week 7. 1.75 g in a week
