Answer:
C. y = 20
Step-by-step explanation:
Given system of equations:
Multiply the second equation by 3:
Subtract this from the first equation to eliminate 3y:
Solve the resulting equation for x:
Substitute the found value of x into the original second equation and solve for y:
Answer:
5 + sqrt(65), 5 - sqrt(65)
Step-by-step explanation:
x + y = 10
x×y = -40
so, two equations with 2 variables. using one equation to express one variable by the second. and then using the second equation to solve and calculate the second variable. and then by knowing the second variable we calculate the first.
=> x = 10 - y
=> (10-y)×y = -40
=> -1×(10-y)×y = 40
=> (y-10)×y = 40
=> y^2 - 10×y - 40 = 0
remember the solution for a quadratic equation
a×x^2 + b×x + c
is
x = (-b ± sqrt(b^2 - 4×a×c)/(2×a)
in our case
a = 1
b = -10
c = -40
and we used "y".
so,
y = (--10 ± sqrt((-10)^2 - 4×1×(-40))/(2×1) =
= (10 ± sqrt(100 + 160))/2 = (10 ± sqrt(260))/2 =
= (10 ± sqrt (4×65))/2 = 10/2 ± 2×sqrt(65)/2 =
= 5 ± sqrt(65)
=>
for y = 5 + sqrt(65), x = 10 - 5 - sqrt(65) = 5 - sqrt(65)
for y = 5 - sqrt(65), x = 10 - 5 + sqrt(65) = 5 + sqrt(65)
Add 1 to 34 four times.
35, 36, 37, 38.
38 is your final answer.
Answer:
896 metres per minute
Step-by-step explanation:
not for much sure
