A=1/2 (b1+b 2)(h) is the area of a trapezoid
<h3>Given</h3>
... r + 7 = 9
<h3>Find</h3>
... r
<h3>Solution</h3>
Subtract 7 from both sides of the equation.
... r + 7 - 7 = 9 - 7
... r = 2 . . . . . . simplify
Expressed as a solution set, this may look like ...
... r ∈ {2}
_____
You probably had no trouble solving this in 2nd grade when it was shown to you in the form ...
__ + 7 = 9
25% or 1/4 in chance. 4 marbles and 16 other colours. 4/16=1/4=25%
4s + 5 = 19
First, subtract 5 from both sides. / Your problem should look like: 4s = 19 - 5.
Second, simplify 19 - 5 to 14. / Your problem should look like: 4s = 14.
Third, divide both sides by 4. / Your problem should look like: s =

.
Fourth, simplify

to

. / Your problem should look like: s =

which is the answer.