Best Answer

Subtract 21 from both sides.

If that's + 4t, the answer is (t - 3)(t + 7) and t = 3, -7

If that's - 4t, the answer is (t + 3)(t - 7) and t = -3, 7

Q: How do you solve the quadratic equation t2 4t equals 21 by factoring?

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y=b+x+x^2 This is a quadratic equation. The graph is a parabola. The quadratic equation formula or factoring can be used to solve this.

y=±√15

Using the quadratic equation formula: x = 8.42 or x = -1.42

x2+3x+2=0 (x+2)(x+1)=0 x=-2 or -1

Pros: There are many real life situations in which the relationship between two variables is quadratic rather than linear. So to solve these situations quadratic equations are necessary. There is a simple equation to solve any quadratic equation. Cons: Pupils who are still studying basic mathematics will not be told how to solve quadratic equations in some circumstances - when the solutions lie in the Complex field.

Related questions

y=b+x+x^2 This is a quadratic equation. The graph is a parabola. The quadratic equation formula or factoring can be used to solve this.

It means you are required to "solve" a quadratic equation by factorising the quadratic equation into two binomial expressions. Solving means to find the value(s) of the variable for which the expression equals zero.

(3x+4)(3x-4)=0 x=±4/3

Solve by factoring. Solve by taking the square root of both sides.

When the equation is a polynomial whose highest order (power) is 2. Eg. y= x2 + 2x + 10. Then you can use quadratic formula to solve if factoring is not possible.

To find the solution to this equation, you need to rearrange the terms and solve for the variable. 4 = 2b + b^2 can be rewritten as b^2 + 2b - 4 = 0. You can then solve this quadratic equation by factoring, completing the square, or using the quadratic formula.

y=±√15

Four? Factoring Graphing Quadratic Equation Completing the Square There may be more, but there's at least four.

Quadratic equation formula

Using the quadratic equation formula:- x = 3.795831523 or x = -5.795831523

The discriminant for the quadratic is b2-4ac = 302 - 4*4*45 = 900 - 720 = 180 Since 180 is not a perfect square, the roots of the equation are irrational and it is far from straightforward to solve such an equation by factoring.

7r2 = 70r-175 Rearrange the equation and treat it as a quadratic equation: 7r2-70r+175 = 0 Divide all terms by 7: r2-10+25 = 0 Solve by factoring or using the quadratic equation formula or by completing the square: (r-5)(r-5) x = 5 and x also = 5 (they both have equal roots)