Step 1 ax2 + bx + c = 0 Step 2 ax2 + bx = − c
Step 3 x2 + b over a times x equals negative c over a
Step 4 x2 + b over a times x plus b squared over 4 times a squared equals negative c over a plus b squared over 4 times a squared
Step 5 x2 + b over a times x plus b squared over 4 times a squared equals negative 4 multiplied by a multiplied by c, all over 4 multiplied by a squared plus b squared over 4 times a squared
Step 6 the square of the quantity x plus b over 2 times a equals b squared minus 4 multiplied by a multiplied by c, all over 4 times a squared
Step 7 x plus b over 2 times a equals plus or minus square root of the quantity b squared minus 4 times a times c over 4 times a squared equals plus or minus square root of b squared minus 4 times a times c, all divided by 4 times a
Step 8 x = −negative b over 2 times a plus or minus square root of b squared minus 4 times a times c, all divided by 2 times a
Step 9 x = negative b plus or minus square root of b squared minus 4 times a times c, all divided by 2 times a

Which of the following is the first incorrect step?