Find the value of x, if a + 7 = 0; b + 10 = 0 and 12x² = ax - b.

Use the substitution 2x + 3 = y to solve for x, if 4(2x + 3)² - (2x + 3) - 14 = 0.

If x² - 3x + 2 = 0, values of x correct to one decimal place are :

1. 2.0 and 1.0

2. 2.0 or 1.0

3. 3.0 and 2.0

4. 3.0 or 2.0