Hello Kaz,

a. For the line to be parallel the slope of both lines have be same. The equation given to you is in standard form. So, first bring the equation in slope-intercept form.

3x + 4y = 7

-3x -3x

________________

4y = -3x + 7

(4y)/4 = (-3x + 7)/4

y = (-3/4)x + 7/4 --------(slope-intercept form)

Slope is -3/4 and line passes through the point (-2/3, 7/8). Use your point-slope formula.

y - y_{1} = m(x - x_{1})

y - 7/8 = -3/4(x - (-2/3))

y = -(-3/4)x + 3/8 --------------------(answer)

b) For line to be perpendicular the slope of line will be negative reciprocal or if you multiply the slope of both lines the result should be -1. So, as we know the slope of the given line is -3/4. Slope of perpendicular line will be 4/3. To check mutiply both slopes (-3/4) * (4/3). You'll get -1. Now, that we've got the slope 4/3 and passes through points (-2/3, 7/8). Again use the point-slope formula

y - y_{1} = m(x - x_{1})

Sustitute, the values and solve. You'll get the answer.

Good luck.