Astudent answers 90% of the questions on a math exam correctly. if he answers 18 questions correctly, how many questions are on the exam?

x=total questions on quiz

90/100=18/x

1800=90x

x=20

There were 20 questions on the quiz.

2x^2+5x+17

your welcome. : )

5=812a+9+3

step 1: simplify both sides of the equation.

5=812a+9+3

5=(812a)+(9+3)(combine like terms)

5=812a+12

5=812a+12

step 2: flip the equation.

812a+12=5

step 3: subtract 12 from both sides.

812a+12−12=5−12

812a=−7

step 4: divide both sides by 812.

812a /812 = -7/812

a= -1/116

so the answer is

a=   -1/116