(5 x2 + 8x - 7) - (2 x2 - 2x - 12), 2) (2x - 3) + ( - 2 x7 - 5x - 18), 3) (6 đ - 3a + 11) - (-3a - a? + 7), 4）（1481-92-333）-（-383+54）-403）， 5) (7 ав - 15а6 + 3а?6) + (30ав - 8а 6).

Let's simplify each expression step-by-step. 1) \( (5x^2 + 8x - 7) - (2x^2 - 2x - 12) \) \[ = 5x^2 + 8x - 7 - 2x^2 + 2x + 12 = (5x^2 - 2x^2) + (8x + 2x) + (-7 + 12) = 3x^2 + 10x + 5 \] 2) \( (2x - 3) + (-2x^7 - 5x - 18) \) \[ = 2x - 3 - 2x^7 - 5x - 18 = -2x^7 + (2x - 5x) + (-3 - 18) = -2x^7 - 3x - 21 \] 3) \( (6d - 3a + 11) - (-3a - a^2 + 7) \) \[ = 6d - 3a + 11 + 3a + a^2 - 7 = a^2 + 6d + (-3a + 3a) + (11 - 7) = a^2 + 6d + 4 \] 4) \( (1481 - 92 - 333) - (-383 + 54) - 403 \) \[ = (1481 - 92 - 333 ) + 383 - 54 - 403 = 1481 - 92 - 333 + 383 - 54 - 403 = 982 \] 5) \( (7ab - 15a^6 + 3a^?6) + (30ab - 8a^6) \) Assuming \( 3a^?6 \) is a typo for \( 3a^6 \), \[ = 7ab - 15a^6 + 3a^6 + 30ab - 8a^6 = (7ab + 30ab) + (-15a^6 + 3a^6 - 8a^6) = 37ab - 20a^6 \]