### Home > CC4 > Chapter A > Lesson A.1.4 > Problem A-42

A-42.

Evaluate each equation below. Homework Help ✎

For

*f*(*x*) = 2 + 3*x*, what is the value of*f*(4)?For

*a*= 4 − 5*c*when*c*= −, what is the value of *a*?For

*n*= 3*d*^{2}− 1 when*d*= −5 , what is the value of*n*?For

*h*(*x*) = −4(*x*− 2), what is the value of*h*(−1)?For 3 +

*k*=*t*when*t*= 14, what is the value of*k*?

Rewrite the expression, substituting in the known variable.

*y* = 2 + 3(4)*y* = 2 + 12

*y* = 14

See part (a) for a strategy to evaluate this expression.

Remember to pay attention to negative signs.

*a* = 6.5

Rewrite the expression, substituting in the known variable.

*n* = 3(−5)² − 1*n* = 3(25) − 1*n* = 75 − 1

*n* = 74

Refer to parts (a) and (c).

Rewrite the problem, substituting in the known variable and then rearrange the problem to make it equal to the unknown variable.