SOLUTION: find the value of x to 3 d.p when: x^2 + 20x = 400cm^2

Question 459676: find the value of x to 3 d.p when:
x^2 + 20x = 400cm^2
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
x^2 + 20x = 400cm^2
Units aren't usual in a quadratic.
x^2 + 20x - 400 = 0

Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)

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=2000 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: 12.3606797749979, -32.3606797749979. Here's your graph:

---------
x = 12.36 cm
x = -32.36 cm
Good luck with the -32 cm

RELATED QUESTIONS
please help me solvethe polynominal ax^3-20x^2+x+3, where a is a constant is denoted by... (answered by Alan3354)

1.Find the value of 20x when x=10? 2.find the value of 3a when a=-4? 3.find the... (answered by checkley71)

Two polynomials P and D are given. Use either synthetic or long division to divide P(x)by (answered by ikleyn)

Find the other factors of P(x)=x^5-x^4-20x^3+20x^2+64x-64 if you are given that x-4 and... (answered by josgarithmetic,solver91311,ikleyn)

find the value of p and q when the polynomial (x*x*x)+ p(x*x)+ qx + 6 gives remainder 3... (answered by stanbon)

a Polynomial P(x) and a divisor d(x) are given. Use long division to find the quotient... (answered by KMST)

Use long division to find the quotient Q(x) and the remainder R(x) when p(x) is divided... (answered by jsmallt9)

The are of a rectangle is 400cm^2. If the length of one of its sides is "x"cm, express... (answered by josgarithmetic)

find the zeros of the function f(x)= x^3+x^2-20x.... (answered by rapaljer)