Answer:
9
Step-by-step explanation:
a^2 +b
Let a = -2 and b = 5
(-2)^2 +5
Exponents first
4 +5
Then add
9
Answer:
200 minutes
Step-by-step explanation:
14 + 0.09 x = 18 + 0.07 x
0.09 x - 0.07 x = 18 - 14
0.02 x = 4
x = 400/2 = 200
Answer:
2/10 miles
Step-by-step explanation:
2 x 1/10 = 2/10
Answer: 490 grams of the first alloy should be used.
30 grams of the second alloy should be used.
Step-by-step explanation:
Let x represent the weight of the first alloy in grams that should be used.
Let y represent the weight of the second alloy in grams that should be used.
A chemist has two alloys, one of which is 15% gold and 20% lead. This means that the amount of gold and lead in the first alloy is
0.15x and 0.2x
The second alloy contains 30% gold and 50% lead. This means that the amount of gold and lead in the second alloy is
0.3y and 0.5y
If the alloy to be made contains 82.5 g of gold, it means that
0.15x + 0.3y = 82.5 - - - - - - - - - - - -1
The second alloy would also contain 113 g of lead. This means that
0.2x + 0.5y = 113 - - - - - - - - - - - - -2
Multiplying equation 1 by 0.2 and equation 2 by 0.15, it becomes
0.03x + 0.06y = 16.5
0.03x + 0.075y = 16.95
Subtracting, it becomes
- 0.015y = - 0.45
y = - 0.45/- 0.015
y = 30
Substituting y = 30 into equation 1, it becomes
0.15x + 0.3 × 30 = 82.5
0.15x + 9 = 82.5
0.15x = 82.5 - 9 = 73.5
x = 73.5/0.15
x = 490
Answer: 3
You can find slope by using the 'rise over run' method. Find 2 clear points and count the number of units between those points, across the x axis and up the y axis. You should have 3/1 (y/x) as your slope.
