Question

If 3x + 3y = 4 and 2x + 7y = 8, then what is x?

Answer 1

I will try to solve your system of equations.

3x+3y=4;2x+7y=8

Step: Solve3x+3y=4for x:

3x+3y+−3y=4+−3y(Add -3y to both sides)

3x=−3y+4

3x3=−3y+43(Divide both sides by 3)

x=−y+43

Step: Substitute−y+43forxin2x+7y=8:

2x+7y=8

2(−y+43)+7y=8

5y+83=8(Simplify both sides of the equation)

5y+83+−83=8+−83(Add (-8)/3 to both sides)

5y=163

5y5=1635(Divide both sides by 5)

y=1615

Step: Substitute1615foryinx=−y+43:

x=−y+43

x=−1615+43

x=415(Simplify both sides of the equation)