How do you factor 3x^2 +10x - 83x2+10x8?

2 Answers
Apr 1, 2018

(3x-2)(x+4)(3x2)(x+4)

Explanation:

3x^2+10x-83x2+10x8

first multiply 33 with -88 and we get -2424

then find two numbers that if we add or subtract we get +10+10 and if we multiply we get -2424

and the numbers are +12+12 and -22

then we place those numbers as follow :-

3x^2+12x-2x-83x2+12x2x8

then we group them

(3x^2+12x)(-2x-8)(3x2+12x)(2x8)

now take the common factor out.

3x(x+4)-2(x+4)3x(x+4)2(x+4)

then group the numbers outside of the brackets

(3x-2)(x+4)(3x2)(x+4)

and that is the answer

Proper Solution:-

3x^2+10x-83x2+10x8

3x^2+12x-2x-83x2+12x2x8

(3x^2+12x)(-2x-8)(3x2+12x)(2x8)

3x(x+4)-2(x+4)3x(x+4)2(x+4)

(3x-2)(x+4)(3x2)(x+4)

Apr 1, 2018

(x+4)(3x-2)(x+4)(3x2)

Explanation:

"for a quadratic in "color(blue)"standard form"for a quadratic in standard form

•color(white)(x)ax^2+bx+c ;a!=0xax2+bx+c;a0

"consider the factors of the product ac which sum to b"consider the factors of the product ac which sum to b

3x^2+10x-8larrcolor(blue)"is in standard form"3x2+10x8is in standard form

"with "a=3,b=10" and "c=-8with a=3,b=10 and c=8

"consider factors of "3xx-8=-24" which sum to + 10"consider factors of 3×8=24 which sum to + 10

"the required factors are "+12" and "-2the required factors are +12 and 2

color(blue)"split the middle term using these factors"split the middle term using these factors

3x^2+12x-2x-8larrcolor(blue)"factor by grouping"3x2+12x2x8factor by grouping

=color(red)(3x)(x+4)color(red)(-2)(x+4)=3x(x+4)2(x+4)

"take out the common factor "(x+4)take out the common factor (x+4)

=(x+4)(color(red)(3x-2))=(x+4)(3x2)

rArr3x^2+10x-8=(x+4)(3x-2)3x2+10x8=(x+4)(3x2)