Question

Multiply and simplify 10x(7x^2+9x+6)

Answer 1

10x (7x² +9x +6 )

multiply
—————

10x (7x²) + 10x (9x) +10x (6)

70x³ + 90x² + 60x

simplification
———————

10x (7x² +9x + 6)

10x(7x² + 9x +6)

7x² + 9x + 6 is a quadratic equation ,
in the form of ax² + bx + c
we know , for any quadratic have real roots only when Discriminant=b² -4ac ≥0

D = b² -4ac =(9)² -4 x 7 x 6

D = 81 -168 = -87 <0

hence, no real roots exist of 7x²+9x +6

hence, we can't factorise ,

so, simplest form of this is ------

10x(7x² +9x + 6)

10x (7x²) +10x(9x)² + 10x(6)²

70x³ +90x² + 60x this is simplest form of given expression .