Find the x-intercepts for the parabola defined by the equation below. y = 3x2 + 18x + 15

1 answer:

4 0

Using quadratic formula
x = [-18 +-sq root (324 -4 *3*15)] / 2*3
x = [-18 +-sq root (144)]/6
x1 = (-18 + 12) / 6 = -1
x2 = (-18 -12) / 6 = -30/6 = -5

You might be interested in

Solve the following equations mentally 1. 5 – x = 8 2. -1 = x – 2 3. -3x = 9 4. -10 = -5x

Ghella [55]

Answer:

1. 5 – x = 8 , x = -3

2. -1 = x – 2 , x = 1

3. -3x = 9 , x = -3

4. -10 = -5x , x= 2

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

Why is it mathematically legal to multiply 2 √ 2 by √ 2 √ 2 in order to rationalize the denominator?

Gala2k [10]

Well if you're referring to rationalizing $\bf \cfrac{2}{\sqrt{2}}$ , which simply means, getting rid of the pesky radical at the bottom

well, it boils down to, hmm say... a quantity or even a polynomial, multiplied times 1, is itself, 2*1=2, 3*1 = 3, ducks*1 = ducks, spaghetti * 1 = spaghetti

or whatever * 1 = whatever
and the value of the multiplicand, doesn't change in anyway, is the same thing before and after the multiplication by 1

now....1 can also be a fraction $\bf \cfrac{2}{2}=1\qquad \cfrac{3}{3}=1\qquad \cfrac{1,000,000}{1,000,000}=1
\\\\\\
\cfrac{ducks}{ducks}=1\qquad \cfrac{spaghetti}{spaghetti}=1\qquad \cfrac{cheese}{cheese}=1
\\\\\\
\cfrac{\textit{the quick fox jumped}}{\textit{the quick fox jumped}}=1\qquad \cfrac{whatever}{whatever}=1$

so.. when you're doing $\bf \cfrac{2}{\sqrt{2}}\cdot \cfrac{\sqrt{2}}{\sqrt{2}}\iff \cfrac{2}{\sqrt{2}}\cdot1$

and the value multiplicand doesn't change in any way

now, try this in your calculator $\bf \cfrac{2}{\sqrt{2}}\cdot \cfrac{\sqrt{2}}{\sqrt{2}}\implies \cfrac{2\sqrt{2}}{\sqrt{2^2}}\implies \cfrac{2\sqrt{2}}{2}\implies \sqrt{2}\\\\
-----------------------------\\\\
\textit{check how much is }\cfrac{2}{\sqrt{2}}\textit{ in your calculator}
\\\\\\
\textit{then check how much is }\sqrt{2}\textit{ in it}$