9514 1404 393
Answer:
(x, y) = (1/2, 5)
Step-by-step explanation:
We observe that the y-terms have coefficients 7 and -14. If we want to eliminate the y-terms, we need to multiply 7 by a factor that makes it be the opposite of -14. That factor will be -(-14)/7 = 2.
After multiplying the first equation by 2, we have ...
- 16x +14y = 78
- 4x -14y = -68
Adding these two equations gives ...
20x = 10
Solving for x, we need to divide by 20:
x = 10/20 = 1/2
Substituting this into the first equation, we get ...
8(1/2) +7y = 39
7y = 35 . . . . . . subtract 4
y = 35/7 = 5 . . . divide by 7
Then the solution is (x, y) = (1/2, 5).
_____
<em>Check</em>
We used the first equation to find y, so we know the x- and y-values satisfy the first equation. We need to check the result using the second equation.
4(1/2) -14(5) = -68
2 -70 = -68 . . . . . . . true; result checks OK
Hello! Welcome to Brainly! Let's solve together. :)
To put a number into scientific notation, you multiply it by a power of 10 that will make it a digit 1-10.
As you can see, we can divide by 10, or multiply by 1/10 to get us to 1.3, which is between 1 and 10. How would we get 1.3 to 13? We would multiply by 10!
This gives us our answer below.
1.3(10
)
I hope this helps!
As the ball hits the ground, its height will be equal to 0, so...
-3t² + 12t + 63 = 0
t² - 4t - 21 = 0
Using the Viet's theorem to solve the quadratic equation quicker:
t₁ + t₂ = 4
t₁t₂ = -21
t₁ = -3 - this is not possible because time can't be negative
t₂ = 7
That means, the ball is expected to hit the ground after 7 sec has passed.
80 students would prefer chocolate ice cream over vanilla. 50x.20=20 studentsx4=80 students
