If discriminant of a quadratic equation ax² + bc + c = 0 is equal to zero, then the roots of the equation are :

1. $-\dfrac{b}{2a}$ each

2. $\dfrac{b}{2a}$ each

3. $-\dfrac{a}{2b}$ each

4. $\dfrac{b}{2b}$ each

If the 23rd term of an A.P. exceeds its 32nd term by -18, then its common difference is :

1. 3

2. 2

3. -2

4. 5

If matrix M = $\begin{bmatrix$}[r] 1 & 3 \ -2 & 5 \end{bmatrix}, then the matrix -2M + 2I is :

1. $\begin{bmatrix$}[r] 0 & -6 \ 4 & -8 \end{bmatrix}

2. $\begin{bmatrix$}[r] 0 & -4 \ 6 & 8 \end{bmatrix}

3. $\begin{bmatrix$}[r] 4 & 12 \ 0 & -4 \end{bmatrix}

4. $\begin{bmatrix$}[r] -4 & 0 \ -8 & 6 \end{bmatrix}

An article is bought for ₹ 60,000 and sold at a discount of 10%. If the rate of GST is 18%, then the bill amount is :

1. ₹ 60,720

2. ₹ 77,800

3. ₹ 54, 120

4. ₹ 63,720