Step-by-step explanation:
Explanation:
Given:
−3x2+12x+1=0
This is in the form:
ax2+bx+c=0
with a=−3, b=12 and c=1
In order to decide which method to use, we can first examine the discriminant:
Δ=b2−4ac=122−4(−3)(1)=144+12=156
Since Δ>0 we can tell that the quadratic has 2 distinct real solutions, but because it is not a perfect square we can also tell that those solutions are irrational.
So there is no rational factorisation and we can discount the use of an AC method or similar.
We can use the quadratic formula or we can complete the square.
If we choose to use the quadratic formula, then we find:
x=−b±√b2−4ac2a
x=−b±√Δ2a
x=−(12)±√1562(−3)
x=−12±2√39−6
x=2±√393
When completing the square, note that b=12 is already divisible by a=−3 and by
Which ever coin feels larger is the penny.
The answer is 71.4 miles per hour
11x+3y=103 and y=3x+1.
11x+3(3x+1)=103 -----> plug in (3x+1) for y in the first equation. You will want to distribute the 3 to the 3x+1 to get something that looks like:
11x+9x+3=103 ------> now you want to combine like terms
20x+3=103 ---> subtract 3 from both sides
20x=100 ----> divide both sides by 20
x=5
y=3(5)+1 ---> I like to plug in this to the equation that already has y isolated. 3*5 is 15, add 1 and you find that y=16.
(5, 16) will be your final answer (:
You can use sigma notation to represent an infinite series. For example, ∞∑n=110(12)n−1 is an infinite series. The infinity symbol that placed above the sigma notation indicates that the series is infinite. To find the sum of the above infinite geometric series, first check if the sum exists by using the value of r .
