Factorise 5x^2 + 8x + 3
3 answers
and can you please show steps in how to solve it. Thanks
It is mostly a trial and error thing..
start with the factors of 5
5,1
(5x ) (x )
next, the factors of 3: 1,3; 3,1
you want the cross factors to add to 8, so 5+3 =8
(5x+1)(x+3) gives 16x as the middle term , so it must be
(5x+3)(x+1)
start with the factors of 5
5,1
(5x ) (x )
next, the factors of 3: 1,3; 3,1
you want the cross factors to add to 8, so 5+3 =8
(5x+1)(x+3) gives 16x as the middle term , so it must be
(5x+3)(x+1)
EXPLANATION:for example x^2 -5x+6 first of al the product =6*x^2=6x^2(first and last term) sum=-5x(2nd term) now find 2 terms dat when u add give -5x and product 6x^2 [(terms ar -3x&-2x)since -*-=+ &-+-=-] now it bcoms x^2-3x-2x+6, factorise=x(x-3)-2(x-3)=(x-2)(x-3) (collectin like terms)
now 5x^2 +8x+3 (product 15x^2 &sum 8x)term 5x&3x (ans=(5x+3)(x+1) same way as the above solution
try this x^2+x+13(it seems the above method don't work, in expresin like this u can use completin the square mtd or form
now 5x^2 +8x+3 (product 15x^2 &sum 8x)term 5x&3x (ans=(5x+3)(x+1) same way as the above solution
try this x^2+x+13(it seems the above method don't work, in expresin like this u can use completin the square mtd or form
1 answer