Copy of Chapter 2 practice

In the [math]xy[/math]-plane, the line determined by the points [math](4,c)[/math] and [math](c,9)[/math] passes through the origin. What is the value of [math]c[/math]?

Function [math]f[/math] is defined by [math]f(x)=a^{-x}+b[/math] where [math]a[/math] and [math]b[/math] are constants. If the [math]y[/math]-intercept of [math]f[/math] is [math]8[/math] and the summation of [math]a[/math] and [math]b[/math] is 10, what is [math]f(2)[/math]?

Test 1