SOLUTION: What is x squared plus 5x plus 4

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Question 646778: What is x squared plus 5x plus 4
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E2+%2B5x+%2B4..........expression-quadratic function and if you set it equal to zero, it will be quadratic equation and you can find 2 roots, and plot the graph which is a parabola
x%5E2+%2B5x+%2B4=0
let's find the roots using quadratic formula:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+...note, in your equation, a=1, b=5 and c=4
x+=+%28-5+%2B-+sqrt%28+5%5E2-4%2A1%2A4+%29%29%2F%282%2A1%29+
x+=+%28-5+%2B-+sqrt%28+25-16+%29%29%2F2+
x+=+%28-5+%2B-+sqrt%28+9+%29%29%2F2+
x+=+%28-5+%2B-+3%29%2F2+
roots:
x+=+%28-5+%2B+3%29%2F2+

x+=+-2%2F2+

x+=+-1
or
x+=+%28-5-3%29%2F2+

x+=+-8%2F2+

x+=+-4
let's see it on a graph:
+graph%28+600%2C+600%2C+-10%2C10%2C+-10%2C+10%2C+x%5E2+%2B5x+%2B4%29+

there is also another way to find solutions for this function
x%5E2+%2B5x+%2B4=0......replace 5x with x%2B4x
x%5E2+%2Bx+%2B4x+%2B4=0.....group
%28x%5E2+%2Bx%29+%2B%284x+%2B4%29=0
x%28x+%2B1%29+%2B4%28x+%2B1%29=0
%28x+%2B4%29%28x+%2B1%29=0
roots:
if x+%2B4=0...=>...x+=-4
if x+%2B1=0...=>...x+=-1