According to the question the base of the triangle is x, the height is ten less than the product of two and x, this is 2x-10. The area of the triangle is the product of seven and the base, this is 7x.
The area of a triangle is given by:
[tex]A=\frac{b\cdot h}{2}[/tex]
Replace each variable for the given expressions:
[tex]\begin{gathered} 7x=\frac{x\cdot(2x-10)}{2} \\ 7x=\frac{2x^2-10x}{2} \\ 7x=x^2-5x \\ 7=x-5 \\ x=7+5 \\ x=12 \end{gathered}[/tex]
x has a value of 12.
