Factoring polynomials 3x^2+42x+72

3(x + 12)(x + 2)

Step-by-step explanation:

Given

3x² + 42x + 72 ← factor out 3 from each term

= 3(x² + 14x + 24) ← factor the quadratic

Consider the factors of the constant term (+ 24) which sum to give the coefficient of the x- term.

The factors are + 12 and + 2, since

12 × 2 = 24 and 12 + 2 = 14, thus

x² + 14x + 24 = (x + 12)(x + 2) and

3x² + 42x + 72

= 3(x + 12)(x + 2) ← in factored form

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional

7.3

step-by-step explanation: