Algebra
posted by Neil .
Solve the system of equations by an algebraic method. Leave answer in exact form.
4x²  7y² = 21
x² + 2y² = 99

Algebra 
Ron
4x²  7y² = 21 (eq1)
x² + 2y² = 99 (eq2)
> eq14*eq2
>
4x²  7y² = 21 (eq1)
4x²  8y² = 396 4*(eq2)
___________________
15y²=375 (eq3)
> y²=25 (eq4)
Back sub to get
x² + 2(25) = 99
> x² =9950
> x² =49 (eq5)
x =(+/)sqrt(49) (eq6)
###############
# x =(+/)7 # (eq7)
###############
y =(+/)sqrt(25) (eq8)
###############
# y =(+/)5 # (eq9)
###############
You could also use Matrix Methods
Respond to this Question
Similar Questions

algebra
1)What is the 4x^2=y^2+8y+32 answer= either hyperbola or parabola 2)The graph of which equation is a circle? 
Algebra
Is there a difference between solving a system of equations by the algebraic method and the graphical method? 
Algebra 2
Can someone check my answers. Write the following equations in standard form. 1) x^2  2x + y^2 + 4y = 11 answer: (x1)^2 + (y+2)^2 = 16 2) 4x^2 + 24x  y + 34 = 0 answer: y = 4(x3)^2 + 2 3) The graph of which equation is a circle? 
algebra
How would you explain to a 6th grader the difference between solving a system of equations by the algebraic method and the graphical method? 
MaTh = Algebra = help
Solve this system of linear equaiton by an algebraic method. So If I had to solve this the elimination method way, how would I do it? 
algebra
Can someone please help. When you solve a system of equations by the substitution method, how do you determine whether the system of equations is inconsistent? 
algebra
Can someone help me figure this out please? 
Algebra II
Explain, in complete sentences, which method you would use to solve the following system of equations and why you chose that method. Provide the solution to the system. x  3y + 2z = 12 x + 2y + 3z = 6 2x  3y  z = 2 
Algebra
I can find no solution to this system of equations. Solve the system of equations using the substitution method 2x + 4y = 2 2x  y = 4 
Algebra 2
Hey, I just have two questions, Thanks. 1. Find the exact solutions of x²  (y  6)² = 36 and y = x² 2. Solve the system,4x² + y² = 20 and y = 4x.