D, Because 7/15 + 9/15 is 16/15 + 4/15 =20/15 which equals 1 5/15 which turns into 1 1/3
A, 1/21 + 2/21 = 3/21 and that equals 1/7
C, 3/14+3/12 turns into 3/14+5/14= 10/14 - 8/14= 2/14=1/7
I'm pretty sure your right. the answer is mantle.
Answer:
The equation of any straight line, called a linear equation, can be written as: y = mx + b, where m is the slope of the line and b is the y-intercept. The y-intercept of this line is the value of y at the point where the line crosses the y axis.
You add +7 to both sides and then divide by 9 to get the x alone.