Final answer:
The trinomial is rewritten as 7x^2 - 19x - 4 using the substitution x = a + b. To solve for x, we can use the quadratic formula with a = 7, b = -19, and c = -4.
Step-by-step explanation:
To rewrite the trinomial 7(a + b)^2 – 19(a + b) – 4 using substitution, we let x equal a + b. The expression then simplifies to 7x^2 – 19x – 4, which is easier to work with. If we need to solve for x, we can apply the quadratic formula, which is x = (-b ± √(b^2 - 4ac)) / (2a), where a, b, and c are coefficients of the quadratic equation ax^2 + bx + c = 0. In this case, a = 7, b = -19, and c = -4. Substituting these values into the quadratic formula, we would solve for x.