Evaluating Expressions
Evaluate 3x + 7 when x=4
19!
3(4)+7 = 12+7=19
Simplify
7x+4-3x+8
4x+12
Find x.
4x-9=15
x=6
add 9 to get 4x=24 divide by 6 to get answer
The perimeter P of a rectangle is given by the formula P = 2l + 2w. Evaluate P when length l = 8 cm and width w = 5 cm.
P=26
P=2(8)+2(5)=16+10=26
Evaluate x2-5x+2 when x=-3
26!
(-3)2-5(-3)+2=9+15+2=26
Simplify
5(2x-3)+4x
14x-15
10x-15+4x=14x-15
Find x
x/2-15=30
x=90
add 15 to get
x/2=4
then multiply by 2 to get answer.
A taxi service charges a total cost modeled by the equation C = 3m + 5, where m is the miles driven. Solve 26 = 3m + 5 to find how many miles were driven for a total cost of $26.
m=7 miles
subtract 5 to get
21=3m, divide by 3 to get answer.
Evaluate
(4x+y)/(2z)
when x=5, y=-4 and z=2
4!
(4*5-4)/(2*2)=(20-4)/(4)=16/4=4
Simplify
3(x-4)-2(3x+5)
-3x-22
3x-12-6x-10=-3x-22
Solve.
7x-3=3x+17
x=5
Move x's together to get
4x-3=17, then add 3 to get
4x=20. Divide by 4 to get answer
Temperature in degrees Fahrenheit is calculated using the formula
F=9/5C+32
Evaluate the formula to find the temperature in Fahrenheit when C = 25.
F=77 degrees
F=9/5(25)+32=45+32=77
21
(2*2+3*3)+2^3=(4+9)+8=15+8=21
Simplify
4(2a-b)-3(a-2b)+5
5a+2b+5
8a-4b-3a+6b+5=5a+2b+5
Solve.
3(2x-4)=4(x+1)
x=8
Distribute to get
6x-12=4x+4. Move x's together to get
2x-12=4. Add 12 to get
2x=16. divide by 2 to get answer.
An object's velocity v (in meters per second) after acceleration is given by v = 12 + 6t, where t is time in seconds What is the velocity after 6 seconds?
v=48
v=12+6(6)=12+36=48
Evaluate 2b(a2)-3b when a=3 and b=-2
-30!
2(-2)(32)-3(-2)=2(-2)(9)-3(-2)=-36+6=-30
Simplify
1/2(8x-12)-1/3(6x-15)
2x-1
4x-6-2x+5=2x-1
Find x.
(2x-5)/3=7
x=13
Multiply by 3 to get
2x-5=21, then add 5 to get
2x=26, then divide by 2 to get answer.
The height h (in feet) of a ball thrown into the air after t seconds is given by
h=-16t^2+80t+5
Evaluate the formula to find the height of the ball at 3 seconds
h=101
-16(3^2)+80(3)+5=-16(9)+240+5=-144+240+5=101