2x+5y=20. , -2x+20y=-90. one solution. infinity many ir no solution. use elimination to find your answer

Which statement best describes how to determine whether f(x) = x squared- x +8 is an even function ?

Grace is standing 18 feet from a lighthouse and kelly is standing 10 feet from grace. the angle that grace looks up to see the top of the lighthouse is 45°. the angle that kelly looks up to see the top of the lighthouse is y°. find the height, h, of the lighthouse. find the angle, rounded to the nearest tenth of a degree, in which kelly looks up to the top of the lighthouse. to the nearest tenth of a degree, find the value of x° . in two or more sentences, explain your calculations

Twice the sum of a number and 2 is equal to three times the difference of the number and 8. find the number.