# Hard SAT Math Question 77 — Video Explanation | 1600.now

Source: https://1600.now/hard/77

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77

$-16(4x-3)^2 + 6(3x-7)^2$  
The given equation above can be rewritten into the form $\frac{a}{13}x^2 + \frac{b}{13}x + \frac{c}{13}$, where $a$, $b$, and $c$ are constants. What is the value of $a + b + c$?