Question

Solve 2x^2-21x-36=0

a. x = -41 or x = 2
b. x = 12 or x = -3/2
c. x = -3/2 or x = 2
d. x = 0 or x = -36

Answer 1

`2x^2-21x-36=0`


`x_(1,\:2)=(-b\pm √(b^2-4ac))/(2a)`


`\mathrm{For\:}\quad a=2,\:b=-21,\:c=-36:\quad x_(1,\:2)=(-\left(-21\right)\pm √(\left(-21\right)^2-4\cdot \:2\left(-36\right)))/(2\cdot \:2)`


`x=(-\left(-21\right)+√(\left(-21\right)^2-4\cdot \:2\left(-36\right)))/(2\cdot \:2):\quad 12`


`x=(-\left(-21\right)-√(\left(-21\right)^2-4\cdot \:2\left(-36\right)))/(2\cdot \:2):\quad -(3)/(2)`


`x=12,\:x=-(3)/(2)`

Answer 2

the answer is B. Hope that help.