 Relevance
• A = lw

10 = x(x + 3)

10 = x^2 + 3x

x^2 + 3x - 10 = 0

(x + 5)(x - 2) = 0

x + 5 = 0, x - 2 = 0

x = - 5, x = 2

disregard x = - 5 since it's a negative number/

solving its dimension

L = 2

w =  x + 3 = 2 + 3 = 5

• (x+3)x=10

=>

x^2+3x=10

=>

x^2+3x-10=0

=>

x^2-2x+5x-10=0

=>

x(x-2)+5(x-2)=0

=>

(x-2)(x+5)=0

=>

x=2 or x=-5 (rejected, for x must not negative)

=>

• The answer is 2 because if you think of all the multiplication facts that have a product of 10, you mostly can find out the answer quickly, for example, the first one that mostly comes to your mind is 5 x 2, but if you do 5 + 3 = 8 x 2, it's 16, that doesn't work. Or, flip it and do 2 x 5, 2 + 3 = 5 x 2 = 10

• A = (x + 3)(x) = 10 cm^2

x^2 + 3x - 10 = (x + 5)(x - 2)

x = 2

• A(x) = x(x + 3) = 10

A(x) = x^2 + 3x = 10

x^2 + 3x - 10 = 0

(x + 5)(x - 2) = 0

x = 2 is the only positive answer.  We must throw out -5, since lengths cannot be negative.

• x*(x + 3) = 10

By inspection x = 2 because 2* 5 = 10

Not necessary to form and solve the quadratic

• x²+3x=10

x=2.

• area = height x width

A = 10 = (x+3)(x)

x² + 3x – 10 = 0

(x + 5)(x – 2) = 0

x = 2 (ignoring negative answer)

rectangle is 2 x 5