X = -6y - 12
4x + 5y =-39
4x + 5y = -39
-4(-6y - 12) + 5y = -39
-4(-6y) + 4(12) + 5y = -39
24y + 48 + 5y = -39
29y + 48 = -39
29y = -87
y = -3
x = -6y - 12
x = -6(-3) - 12
x = 28 - 12
x = 6
(x, y) = (6, -3)
Patterns allow someone to make educated guesses.
Answer: the price for an adult ticket is $3
Step-by-step explanation:
Let x represent the price of one adult ticket.
Let y represent the price of one child ticket.
The Martinez family went to play and paid $13 for 1 adult and 4 children. This means that
x + 4y = 13 - - - - - - - - - - -1
The Hernandez family went to the same place and paid $14 for 3 adults and 2 children. This means that
3x + 2y = 14 - - - -- - - - - - - -2
Multiplying equation 1 by 3 and equation 3 by 1, it becomes
3x + 12y = 39
3x + 2y = 14
Subtracting, it becomes
10y = 25
y = 25/10 = 2.5
Substituting y = 2.5 into equation 1, it becomes
x + 4 × 2.5 = 13
x + 10 = 13
x = 13 - 10
x = 3
Answer:
Step-by-step explanation:
This is a quadratic expression. Use the quadratic formula to find the roots, and then once you have the roots, write the corresponding factors.
The coefficients of this quadratic expression are a = 7, b = 5 and c = -3
The discriminant is b^2 - 4ac, or 5^ - 4(7)(-3), or 25 + 84 = 109. Because this is positive, we know that the expression has two unequal, real roots.
Using the quadratic formula, we now find these roots:
-b ± √(discriminant)
x = -------------------------------- which here is:
2a
-5 ± √109
x = -----------------
14
The factors can be found from these two roots. The first one is
-5 - √109 5 + √109
(x - ---------------- ) = (x + ---------------- )
14 14
and the second is
5 - √109
(x + ---------------- )
14
