The answer would be -21.6
There are 5 solutions for this system.
x^2 + 4y^2 = 100 ____1
4y - x^2 = -20 ____2
Add both 1 & 2 together. x^2 gets cancelled
4y^2 + 4y = 80 (send 80 to the other side and divide by 4)
Then equation the becomes : y^2 + y -20 =0
Now factorise the equation: (y+5) (y-4) = 0
Solve for y : y = -5 and y = 4
Using the values of y to find the values of x. From equation 1:
x^2 = 100 - 4y^2 x = /100 - 4y^2 (/ means square root) Replace values of y
y = -5, x = /100 - 4(-5)^2 = /100 - 100 = 0
y = 4, x = /100 - 4(4)^2 = / 100 - 64 = /36 = -6 or 6
Thus we have 6 solutions y = -5, 4 and x = -6, 0, 6
A solution to a division problem means it is the quotient. And it tells us the solution to the dividend and divisor.
Answer:
3 3/7 or 24/7 mins
Step-by-step explanation:
Let total job = X
Jeff's rate = X/6
Bob's rate = X/8
Combined rate = X/6 + X/8
(4X × 3X)/24 = 7X/24
7X/24 = X/T
T = X ÷ (7X/24)
T = X × (24/7X)
T = 24/7 mins
Shortcut:
T = product of individual times/sum of individual times
T = (6×8)/(6+8)
T = 48/14
T = 24/7
T = 3 3/7 mins
