Originally Posted by

**studley89**
Hi all. I have been given the following and am not confident i have got the units correct so was hoping someone could help me.

d.The equation for a straight line is often used in science to find an unknown without reference to a graph. For a set of data for two quatities, *A* and *B*, where *A* is plotted on the *x*-axis and *B* on the *y*-axis, the gradient of the straight line is 2.3 × 10^{4}m s^{−1} and the intercept on the *y*-axis is 5.8 × 10^{4} m. Using the equation for a straight line (Book 3, Equation 7.12 ) as your starting point, determine the value for *A *when *B* = 6.2 × 10^{5} m. Show all your workings and give your answer in scientific notation and to two significant figures.

Y =mx + c

C = 5.8 × 10^{4} m

M= 2.3 × 10^{4}m s^{−1}

*B* = 6.2 × 10^{5} m

6.2 × 10^{5} m 2.3 × 10^{4}m s^{−1} A 5.8 × 10^{4} m

6.2 × 10^{5} m - 5.8 × 10^{4} m = 2.3 × 10^{4}m s^{−1} A

620000m – 58000 m s^{−1}= 23000 m A

562000 s = 23000m A

__562000s __= A

23000m

24.434782608695652173913043478261s = A

A = 24s to 2 significant figures.