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The equation of tangent line to y=2x2+7y = 2x^2 + 7, which is parallel to the line 4x−y+3=04x - y + 3 = 0 is

Solution

✅ Correct Option: 3

When two lines are parallel, they have the same slope.

Given line: 4x−y+3=04x - y + 3 = 0

Rearranging to slope-intercept form:

−y=−4x−3-y = -4x - 3

y=4x+3y = 4x + 3

The slope of the given line is 44.

The tangent line must also have slope 44.


For the curve y=2x2+7y = 2x^2 + 7, the derivative gives the slope at any point:

dydx=4x\frac{dy}{dx} = 4x

Setting the derivative equal to 44:

4x=44x = 4

x=1x = 1


Substituting x=1x = 1 into the original equation:

y=2(1)2+7y = 2(1)^2 + 7

y=2+7y = 2 + 7

y=9y = 9

The point of tangency is (1,9)(1, 9).


Using point-slope form with slope 44 and point (1,9)(1, 9):

y−9=4(x−1)y - 9 = 4(x - 1)

y−9=4x−4y - 9 = 4x - 4

y=4x+5y = 4x + 5

4x−y+5=04x - y + 5 = 0

Therefore, the equation of the tangent line is 4x−y+5=04x - y + 5 = 0.

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