Identify a, b, c: Identify a, b, and c in the quadratic expression 2q2−9q+7. Compare 2q2−9q+7 with ax2+bx+c. a=2b0b1
Find product and sum: Find two numbers whose product is a∗c (2∗7=14) and whose sum is b (−9).We need to find two numbers that multiply to 14 and add up to −9.After checking possible pairs of factors of 14 (1 and 14, 2 and 2∗7=140), we find that none of these pairs add up to −9.This means we cannot factor the quadratic expression using simple factorization methods.
Use quadratic formula: Since the quadratic expression cannot be factored easily, we will use the quadratic formula to find the roots of the equation 2q2−9q+7=0.The quadratic formula is q=2a−b±b2−4ac.Let's calculate the discriminant b2−4ac first.Discriminant = (−9)2−4(2)(7) = 81−56=25.Since the discriminant is a perfect square, we can find exact roots.
Calculate discriminant: Calculate the roots using the quadratic formula.q=2⋅2−(−9)±25q=49±5We have two possible values for q:q1=4(9+5)=414=3.5q2=4(9−5)=44=1
Calculate roots: Write the factored form using the roots found.The factored form of the quadratic expression is (q−q1)(q−q2).Substitute q1 and q2 into the factored form.Factored form: (q−3.5)(q−1)However, we started with integer coefficients, so we should express the roots as fractions to maintain the form.q1=27 (since 3.5 is 27)Factored form: (q−27)(q−1)To clear the fraction, multiply each term by 2.Factored form: (2q−7)(q−1)