factorise x^2+3x-180
Answers
Factoring x2+3x-180
The first term is, x2 its coefficient is 1 .
The middle term is, +3x its coefficient is 3 .
The last term, "the constant", is -180
Step-1 : Multiply the coefficient of the first term by the constant 1 • -180 = -180
Step-2 : Find two factors of -180 whose sum equals the coefficient of the middle term, which is 3 .
-180 + 1 = -179
-90 + 2 = -88
-60 + 3 = -57
-45 + 4 = -41
-36 + 5 = -31
-30 + 6 = -24
-20 + 9 = -11
-18 + 10 = -8
-15 + 12 = -3
-12 + 15 = 3 That's it
Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, -12 and 15
x2 - 12x + 15x - 180
Step-4 : Add up the first 2 terms, pulling out like factors :
x • (x-12)
Add up the last 2 terms, pulling out common factors :
15 • (x-12)
Step-5 : Add up the four terms of step 4 :
(x+15) • (x-12)
Which is the desired factorization
Answer:
(x-12)(x+15)
Step-by-step explanation:
x^2+15x-12x-180=0
x(x+15)-12(x+15)=0
(x-12)(x+15)=0
x=12. or. x=-15
solution set {-15,12}