SOLUTION: Could someone please show me how to do this? Find the x-intercepts. {{{y=x^2+4x}}}

Question 102747: Could someone please show me how to do this? Find the x-intercepts.
Found 2 solutions by bucky, MathLover1:
Answer by bucky(2189) (Show Source): You can put this solution on YOUR website!
An x-intercept is a point on the x-axis where the graph of the function crosses the x-axis.
But any (x,y) point on the x-axis has zero as its y-value. So to find the intercept
points on the x-axis, set y equal to zero and solve for the corresponding values of x. So
let's do that ... set y = 0 in the given function of . When you do that
you get:
.

.
Let's transpose this ... switch sides around ... to get it in the little more standard form
of:
.

.
Since the two terms on the left side both contain x, we can factor an x from each of the
terms to make the equation become:
.

.
This equation will be true if either one of the factors equals zero because multiplying
the left side by zero will make it equal the right side which is zero.
.
So the equation will be true if either x = 0 or x + 4 = 0. In the second factor this means
that x = -4. Since we already know that y is zero for these two values, the x-intercept
points are (0, 0) and (-4, 0).
.
That's all there is to it.
.
Hope this helps you to understand that to find x-intercepts you set y equal to zero and solve
for the corresponding values of x.
.
Answer by MathLover1(20850) (Show Source): You can put this solution on YOUR website!

The x-intercepts are where the graph crosses the x-axis, and the y-intercepts are where the graph crosses the y-axis.

Find x for what y = o

this product is equal to 0 if or is equal to 0
Solutions:

Here is the graph:

Solved by pluggable solver: SOLVE quadratic equation with variable

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=16 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: 0, -4. Here's your graph:

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