Answer:
690
Step-by-step explanation:
Round from the tens place.
Given:
The function, f(x) = -2x^2 + x + 5
Quadratic equation: 0 = -2x^2 + x +5
where a = -2
b = 1
c = 5
The discriminate b^2 - 4ac = 41
To solve for the zeros of the quadratic function, use this formula:
x = ( -b +-√ (b^2 - 4ac) ) / 2a
x = ( 1 + √41 ) / 4 or 1.85
x = ( 1 - √41 ) / 4 or -1.35
Therefore, the zeros of the quadratic equation are 1.85 and -1.35.
Let x = amount of 45% antifreezeLet y = amount of 70% antifreeze EQUATION 1: x + y = 150 (total of 150 gallons mixed) EQUATION 2: .45x + .75y = .55(x + y) Simplify and solve the system of equations Multiply second equation by 100 on both sides to remove the decimals 45x + 75y = 55(x + y) Combine like terms 45x + 75y = 55x + 55y 45x - 55x + 75y - 55y = 0 -10x + 20y = 0 Now we have the following system of equations: x + y = 150 -10x + 20y = 0 Multiply the first equation by -10 to get opposite coefficients for x; add the equations to eliminate x 10x + 10y = 1500 -10x + 20y = 0 ------------------------------ 30y = 1500 Solve for y 30y = 1500 y = 50 Since the total mixed gallons is 150, x = 150 - 50 = 100 So we need 100 gallons of the 45% antifreeze and 50 gallons of the 70% antifreeze
