Welcome :: Homework Help and Answers :: Mathskey.com

Recent Visits

    
Welcome to Mathskey.com Question & Answers Community. Ask any math/science homework question and receive answers from other members of the community.

13,435 questions

17,804 answers

1,438 comments

774,039 users

Solve the following Quadratic Equations using the Quadratic Formula

0 votes

Solve the following Quadratic Equations using the Quadratic Formula

asked Oct 6, 2018 in ALGEBRA 1 by anonymous

1 Answer

0 votes
1)
x^2 + 4x - 21   =  0
Compare it to quadratic form ax^2 + bx + c  =  0
a = 1, b = 4, c = -21
Roots are  
x  =  [ - b ± √(b^2 - 4ac) ] / 2a
x  =  [ - (4) ± √((4)^2 - 4(1)(-21)) ] / 2(1)
x  =  [ - 4 ± √(16 + 84) ] / 2
x  =  [ - 4 ± √100 ] / 2
x  =  [ - 4 ± 10 ] / 2
x  =  [ - 4 + 10 ] / 2      ;       x  =  [ - 4 - 10 ] / 2
x  =  6 / 2      ;       x  =  - 14 / 2
x  =  3           ;       x  =  - 7
2)
3x^2 + 5x - 2   =  0
Compare it to quadratic form ax^2 + bx + c  =  0
a = 3, b = 5, c = -2
Roots are  
x  =  [ - b ± √(b^2 - 4ac) ] / 2a
x  =  [ - (5) ± √((5)^2 - 4(3)(-2)) ] / 2(3)
x  =  [ - 5 ± √(25 + 24) ] / 6
x  =  [ - 5 ± √49 ] / 6
x  =  [ - 5 ± 7 ] / 6
x  =  [ - 5 + 7 ] / 6      ;        x  =  [ - 5 - 7 ] / 6
x  =  2 / 6      ;        x  =  - 12 / 6
x  =  1 / 3      ;        x  =  - 2
Answer :

1)  The Solutions are  x  =  3   and   x  =  - 7

2)  The Solutions are  x  =  1 / 3   and   x  =  - 2.

answered Oct 10, 2018 by homeworkhelp Mentor

Related questions

...