SOLUTION: Could you show me how to factor by grouping? I have two problems I have been working on but do not understand how to get the final answers to the problems;1.21u^2-40u-21;2.5c^2+18c

Question 317458: Could you show me how to factor by grouping? I have two problems I have been working on but do not understand how to get the final answers to the problems;1.21u^2-40u-21;2.5c^2+18c-35
Answer by JBarnum(2146) (Show Source): You can put this solution on YOUR website!
1.21u^2-40u-21

Solved by pluggable solver: SOLVE quadratic equation with variable

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=1701.64 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: 33.5747683401831, -0.516917100513695. Here's your graph:

5c^2+18c-35

Solved by pluggable solver: SOLVE quadratic equation with variable

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=1024 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: 1.4, -5. Here's your graph:

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