We are asked to "solve" x^2+4x+3:
In the typical Algebra assignment you are asked to either evaluate an expression, simplify and expression, or solve an equation. Each of these, while related, involve a different approach.
We could evaluate x^2+4x+3 for a given value of x; say if x=3 then the expression has the value 3^2+4(3)+3=24.
If we are asked to simplify an expression, we strive to remove grouping symbols (parantheses, brackets, etc...) and then add/subtract like terms.
Here we are asked to "solve" x^2+4x+3. It is implied that we are to solve the general equation x^2+4x+3=0.
(a) You can factor the polynomial:
(x+3)(x+1)=0
** One method is to rewrite the linear term as the sum of two terms where the product of the coefficients is the constant term: x^2+3x+1x+3; then factor by grouping: x(x+3)+1(x+3); use the distributive property to rewrite as (x+3)(x+1)=0 **
Now use the zero product property (if ab=0 then a=0, b=0, or a=b=0) to get:
x+3=0 ==> x=-3 x+1=0 ==> x=-1
So the solutions are x=-1 or -3
(b) You could complete the square:
x^2+4x=-3
x^2+4x+4=-3+4
(x+2)^2=1
x+2=1 or x+2=-1
x=-1 or x=-3
(c) You could use the quadratic formula
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The solutions are x=-1 or x=-3
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