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How do you solve #q^2-21q=-20#?

Answer 1

Savannah Anderson

The solutions are:

# color(green)(q = 20#

# color(green)(q = 1 #

#q^2 - 21 q = -20#

#q^2 - 21 q + 20 = 0 #

The equation is of the form #color(blue)(aq^2+bq+c=0# where:

#a=1, b=-21, c=20#

The source of the discriminant is:

#Delta=b^2-4*a*c#

# = (-21)^2-(4*1 * 20)#

# = 441 - 80 =361#

Typically, the following formula is used to find the solutions:

#q=(-b+-sqrtDelta)/(2*a)#

#q = (-( - 21)+-sqrt(361))/(2*1) = ((21+- 19))/2#

# q= ((21+ 19))/2 = 40 / 2 = 20#

# q= ((21 - 19))/2 = 2 / 2 = 1 #

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Answer 2

Kennedy Adams

To solve the quadratic equation (q^2 - 21q = -20), follow these steps:

Rewrite the equation in standard quadratic form: (q^2 - 21q + 20 = 0).
Factor the quadratic expression: ((q - 1)(q - 20) = 0).
Set each factor equal to zero and solve for (q): (q - 1 = 0) or (q - 20 = 0).
Solve each equation separately: (q = 1) or (q = 20).

So, the solutions to the equation are (q = 1) and (q = 20).

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.