The equation of a straight line is given in the form:
![y=mx+b](https://img.qammunity.org/2023/formulas/mathematics/high-school/smsb8cbft03lwblmi49nf2l6jby2ofxzws.png)
where m is the slope and b is the intercept on the y axis.
The question already provides the value of the slope to be:
![m=28](https://img.qammunity.org/2023/formulas/mathematics/high-school/7u6zbfp8rcy3wv0uk4nrvqinbedz3fmelu.png)
Therefore, the value of b can be gotten by substituting any pair of x and y values into the equation:
![\begin{gathered} y=28x+b \\ Take\text{ }(x,y)=(1,28) \\ \therefore \\ 28=28(1)+b \\ 28=28+b \\ b=28-28 \\ b=0 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/4hz23yxnc8vj38r8ogw0bp6u1c17yo0d1w.png)
The unknown value is 0.
The equation will be:
![\begin{gathered} y=28x+0 \\ or \\ y=28x \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/me1rqvtw6rw7yj339bilvkcvz3dguzpzvp.png)