The base of a triangle is 3 cm longer than its altitude. The area of the triangle is 35cm^2. Find the altitude. (Hint: use the area of a triangle. 1/2 * base * altitude.)

The base is 3 + (x), altitude is x so substitute. Now we know the area of a triangle is base X height X 1/2. Substitute again! 1/2 (3+x) (x) = 35. Multiply both sides by 2 to cancel out the 1/2. Now you have (x) (x+3) = 70 and you have to foil out the left side x^2+3x=70. Subtract 70 on both sides x^2+3x-70=0. Find two numbers that multiply to - 70 and add to 3. Solve (x+10) (x-7) = 0. the x value is 7. since you can't have negative length values. Substitute 7 into 3+x for the base so you know the base is 10 and the height is 7.