Question

Solve the equation by factoring 3x²-42=11x​

Answer 1

`3x^2-42=11x\\3x^2-11x-42=0\\3x^2+7x-18x-42=0\\x(3x+7)-6(3x+7)=0\\(x-6)(3x+7)=0\\x=6 \vee x=-(7)/(3)`

Answer 2

x=-7/3 or x=6

Explanation:

3x²-42=11x

3x²-11x-42

a=3

b=-11

c=-42

we will find that the numbers that their sum is =b & their product is ac(a*c).

b=-11 & ac=3*-42=-126

so the numbers are -18 &7

because -18+7=-11 &-18*7=-126

so

3x²-11x-42

3x²-18x+7x-42

(3x²-18x)(7x-42)

3x(x-6)7(x-6)=0

(x-6) (3x+7)=0

x-6=0 3x+7=0

x=6 3x=-7

3x/3=-7/3

x= -7/3

so the solution is x=6 or x= -7/3