SOLUTION: Please help me: Use the Quadratic formula to solve: 7x(x+3)-9=17x-8

Algebra ->  Finance -> SOLUTION: Please help me: Use the Quadratic formula to solve: 7x(x+3)-9=17x-8      Log On


   

Question 1047876: Please help me:
Use the Quadratic formula to solve:
7x(x+3)-9=17x-8
Found 2 solutions by Alan3354, MathLover1:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Step 1, get it into ax%5E2+%2B+bx+%2B+c+=+0 form

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

7x%28x%2B3%29-9=17x-8

7x%5E2%2B21x-9=17x-8

7x%5E2%2B21x-9-17x%2B8=0

7x%5E2%2B4x-1=0-> note: a=7,b=4, and c=-1

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+

x+=+%28-4+%2B-+sqrt%284%5E2-4%2A7%2A-1+%29%29%2F%282%2A7%29+

x+=+%28-4+%2B-+sqrt%2816%2B28+%29%29%2F14+

x+=+%28-4+%2B-+sqrt%2844+%29%29%2F14+

x+=+%28-4+%2B-+sqrt%2811%2A4+%29%29%2F14+

x+=+%28-4+%2B-+2%2Asqrt%2811+%29%29%2F14+

x+=+%28-cross%284%292+%2B-+cross%282%29%2Asqrt%2811+%29%29%2Fcross%2814%297+

x+=+%28-2+%2B-+sqrt%2811+%29%29%2F7+

x+=+%28-2%2F7+%2B-+sqrt%2811+%29%2F7+%29

solutions:
x+=+-2%2F7+%2B+sqrt%2811+%29%2F7+
x+=+-2%2F7+-+sqrt%2811+%29%2F7+