-2x2+13x=15

Question

-2x2+13x=15

anonymous · Answer

i think is -3.5

timaashorty · Answer

$$-2 * 2+13x=15 $$
 Or
$$-2x^2+13x=15$$ ?

anonymous · Answer

Solve the quadratic equation 2x^2 - 13x + 15 = 0.(1)
You may use the factoring AC method. Find 2 number b1 and b2 that satisfy the 2 conditions: Product b1*b2 = ac = 30. Sum (b1 + b2) = -13.
Compose factor pairs of a*c = 30: (-1, -30)(-2, -15)(-3, -10). Then b1 = -3 and b2 = -10. Replace in the equation (1), the term -13x by the 2 terms (-3x) and (-10x), then factor.

anonymous · Answer

You may use the new Transforming Method (Google Search) that may be faster and simpler.
Step 1. Transform the equation (1) to the simplified form x^2 -13x + 30 = 0 (2).
Step 2. Solve (2) by the Diagonal Sum Method , when a = 1. Both roots are negative (Rule of Signs). Compose factor pairs of a*c = 30. Proceeding: (-1, -30)(-2, -15)(-3, -10) This last sum is -3 -10 = -13= -b. Then the 2 real roots of 2 are: y1 = -3 , and y2 = -10 
Step 3. Back to the original equation, the 2 real roots are: x1 = y1/2 = -3/2, and x2 = y2/2 = -10/2 = -5