Question

x² +8x+15 slove quardric polynomial ​

Answer 1

${x}^{2} + 8x + 15 = 0 \\ {x}^{2} + 5x + 3x + 15 = 0 \\ x(x + 5) + 3(x + 5) = 0 \\ (x + 3)(x + 5) = 0 \\ x = - 3 \:or - 5$

Answer 2

Answer:

Step-by-step explanation:

now find the roots of the equation

take the product of the roots=15=c/a=15/1=15

sum of roots is -b/a=-8/1=-8

so we have take the roots in such a way that their product must be 15 and their sum must be -8

take -3 and -5

now

x^2+3x+5x+15=0

x(x+3)+5(x+3)=0

x+3)(x+5)=0

x+3=0

x+5=0

x=-3,-5

or

we can also find the roots in this way

x=-b+(sqrt(b^2)-4ac)/2a and x=-b-(sqrt(b^2)-4ac)/2a

x=-8+sqrt(64-60)/2 and x=-8-sqrt(64-60)/2

x=-8+2/2 and x=-8-2/2

x=-6/2 and x=-10/2

x=-3 and -5