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The area (in sq. units) of the region bounded by the lines y=2x+3y = 2x + 3, the x – axis and the ordinates x=−2x = -2 and x=2x = 2 is equal to

Solution

✅ Correct Option: 3

The line y=2x+3y = 2x + 3 crosses the x-axis when y=0y = 0:

2x+3=02x + 3 = 0

x=−32x = -\dfrac{3}{2}

This lies inside the interval [−2,2][-2, 2], so:

From x=−2x = -2 to x=−32x = -\dfrac{3}{2}: the line is below the x-axis (y<0)(y < 0)

From x=−32x = -\dfrac{3}{2} to x=2x = 2: the line is above the x-axis (y>0)(y > 0)


Area=∣∫−2−3/2(2x+3) dx∣+∫−3/22(2x+3) dx\text{Area} = \left|\displaystyle\int_{-2}^{-3/2}(2x+3)\,dx\right| + \int_{-3/2}^{2}(2x+3)\,dx

The antiderivative is:

∫(2x+3) dx=x2+3x\displaystyle\int(2x+3)\,dx = x^2 + 3x


For x=−2x = -2 to x=−32x = -\dfrac{3}{2}:

∫−2−3/2(2x+3) dx=[x2+3x]−2−3/2\displaystyle\int_{-2}^{-3/2}(2x+3)\,dx = \Big[x^2+3x\Big]_{-2}^{-3/2}

=(94−92)−(4−6)= \left(\dfrac{9}{4} - \dfrac{9}{2}\right) - \left(4 - 6\right)

=(−94)−(−2)= \left(-\dfrac{9}{4}\right) - (-2)

=−94+2= -\dfrac{9}{4} + 2

=−14= -\dfrac{1}{4}

Taking absolute value → 14\dfrac{1}{4}


For x=−32x = -\dfrac{3}{2} to x=2x = 2:

∫−3/22(2x+3) dx=[x2+3x]−3/22\displaystyle\int_{-3/2}^{2}(2x+3)\,dx = \Big[x^2+3x\Big]_{-3/2}^{2}

=(4+6)−(−94)= (4+6) - \left(-\dfrac{9}{4}\right)

=10+94= 10 + \dfrac{9}{4}

=494= \dfrac{49}{4}


Area=14+494\text{Area} = \dfrac{1}{4} + \dfrac{49}{4}

=504= \dfrac{50}{4}

=252 sq. units= \boxed{\dfrac{25}{2} \text{ sq. units}}

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