<span>replace Y = 5x - 13
into
4x + 3y = 18
</span>
4x + 3 (5x - 13) = 18
4x + 15 - 39 = 18
4x -24 = 18
4x = 18 +24
4x = 42
x = 42/4
x = 10.5
Y = 5(10.5) - 13
= 52.5 - 13
= 39.5
answer: x = 10.5 and y = 39.5
Answer:
A
Step-by-step explanation:
Substitue 15 into the x value and complete the equation.
This is because 2,280 is the original distance. 15 would be the hours and 60 would be how many miles per hour. So we multiply 15 and 60 and get 900, this is how many total miles they have driven. But when we subtract that number from 2,280, and we get 1,380, this is how many miles they have left.
Answer;-1.5238095238
First step; 8/15
8/15 = 0.53 and so on in a repeating form. (0.53333333333)
Divide; 0.53 / -0.35
= -1.5238095238
18 kg of 15% copper and 72 kg of 60% copper should be combined by the metalworker to create 90 kg of 51% copper alloy.
<u>Step-by-step explanation:</u>
Let x = kg of 15% copper alloy
Let y = kg of 60% copper alloy
Since we need to create 90 kg of alloy we know:
x + y = 90
51% of 90 kg = 45.9 kg of copper
So we're interested in creating 45.9 kg of copper
We need some amount of 15% copper and some amount of 60% copper to create 45.9 kg of copper:
0.15x + 0.60y = 45.9
but
x + y = 90
x= 90 - y
substituting that value in for x
0.15(90 - y) + 0.60y = 45.9
13.5 - 0.15y + 0.60y = 45.9
0.45y = 32.4
y = 72
Substituting this y value to solve for x gives:
x + y = 90
x= 90-72
x=18
Therefore, in order to create 90kg of 51% alloy, we'd need 18 kg of 15% copper and 72 kg of 60% copper.
