Grade 8 Math Problems

Grade 8 Math Problems

Introduction to 8th grade math:

In this article you learned how to do 8th grade math. In 8th grade math covers the following topics:

Algebra
Linear algebra
Fraction
Quadratic equation
Algebraic expression
Area of triangle and parallelogram
Polynomial
Probability
In this content we discuss about the algebraic expression and quadratic equation with suitable example problems.


Example problems on 8th grade math:


Simplify the algebraic equation.

x^2 - x = 0

Solution:

Let us take the equation is
x^2 - x = 0

Take the common factor x outside
x (x - 1) = 0

So the product x (x - 1) to be equal to zero, then we get

x = 0 or x - 1 = 0

Solve the above simple equations to obtain the solutions.
x = 0
or
x = 1

Hence the answer is x=0 and x=1

Example problems on 8th grade math:

Solve x^2-15x-100

Solution:

Let P (x) = x^2-15x-100

Step 1: The given polynomial is in the form of ax^2+bx+c =0

a = 1; b =-15; c =-100

Multiply the coefficient of x^2 and the constant term,

1*-100 =-100 (product term)

Step 2: Find the factors for the product term

-100---- > -20*5 = -100 (factors 20 and -5)

-15 ---- >-20+5 =-15 (-15 is the coefficient of x)

Step 3: Divide the coefficient of x as -15

x^2-15x-100=0

x^2+5x-20x-100=0

Step 4: Taking the common term x from the first two terms and -20 from the next two terms

x(x+5) -20(x+5) =0

(x-20) (x+5) = 0.

Now set (x+5) =0; x=-5

(x-20) =0; x=20.

The roots are x=20 and -5.

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Example problems on 8th grade math:


Solve the algebraic expression

4(x -2) + 2y - 3(x -y -4) + 5

Solution:

Given algebraic expression is
4(x -2) + 2y - 3(x -y -4) + 5

Multiplying the integer with above terms

4x - 8 + 2y -3x -3y + 12 + 5

Combine like term
4x-3x +2y -3y -8+12+5

x –y +9

Hence the answer is x-y+9